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Posted to commits@systemds.apache.org by ba...@apache.org on 2021/09/20 11:27:39 UTC

[systemds] 03/03: [SYSTEMDS-2990] Workload tree move decompression to input hop

This is an automated email from the ASF dual-hosted git repository.

baunsgaard pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/systemds.git

commit 61f40bd6af0291c2340974d3a2e1074181a51822
Author: baunsgaard <ba...@tugraz.at>
AuthorDate: Wed Sep 8 17:04:04 2021 +0200

    [SYSTEMDS-2990] Workload tree move decompression to input hop
    
    This commit move the decompression instruction to the input hop
    of a decompressing instruction execution on the workload trees.
    this in practice means that if a variable is used in a forloop
    and needs decompression it is taken into account that the decompression
    only happens once, and outside the for loop.
    
    - Update to allow return of constant column groups in various cases
    - Remove System.out.println from estim estimatorDensityMap
    - Add Compression in loop right mult with decompression
    - Fix Binary matrix matrix operation Compressed
    - Add isDensifying boolean to compression cost, to allow compression
    to compare to dense allocation.
    - add missing minus on empty operator
    
    Closes #1385
---
 .../java/org/apache/sysds/hops/OptimizerUtils.java |   3 +
 .../sysds/hops/estim/EstimatorDensityMap.java      |   4 +-
 .../ipa/IPAPassCompressionWorkloadAnalysis.java    |  22 +-
 .../RewriteAlgebraicSimplificationDynamic.java     |  26 +-
 .../hops/rewrite/RewriteCompressedReblock.java     |   6 +-
 .../runtime/compress/CompressedMatrixBlock.java    | 119 +++++--
 .../compress/CompressedMatrixBlockFactory.java     |  18 +-
 .../runtime/compress/CompressionSettings.java      |   8 +-
 .../compress/CompressionSettingsBuilder.java       |   4 +-
 .../runtime/compress/CompressionStatistics.java    |   4 +-
 .../runtime/compress/DMLCompressionException.java  |  12 +-
 .../runtime/compress/cocode/CoCodeGreedy.java      |   8 +-
 .../runtime/compress/colgroup/ColGroupFactory.java |   4 +-
 .../compress/colgroup/ColGroupUncompressed.java    |   7 +-
 .../runtime/compress/colgroup/ColGroupValue.java   |   6 -
 .../compress/colgroup/mapping/MapToFactory.java    |  11 +-
 .../compress/cost/ComputationCostEstimator.java    |  48 ++-
 .../compress/cost/CostEstimatorBuilder.java        |  34 +-
 .../compress/cost/CostEstimatorFactory.java        |  10 +-
 .../compress/cost/InstructionTypeCounter.java      |   2 +
 .../compress/estim/CompressedSizeEstimator.java    |   4 +-
 .../estim/CompressedSizeEstimatorExact.java        |   3 +-
 .../estim/CompressedSizeEstimatorFactory.java      |   2 +-
 .../estim/CompressedSizeEstimatorSample.java       |   5 +-
 .../compress/estim/CompressedSizeInfoColGroup.java |   2 +-
 .../runtime/compress/estim/EstimationFactors.java  |   2 +-
 .../sysds/runtime/compress/lib/CLALibAppend.java   |   7 +-
 .../runtime/compress/lib/CLALibBinaryCellOp.java   | 116 ++++---
 .../sysds/runtime/compress/lib/CLALibCompAgg.java  |  17 +-
 .../runtime/compress/lib/CLALibLeftMultBy.java     | 102 +++---
 .../runtime/compress/lib/CLALibRightMultBy.java    |  82 ++---
 .../readers/ReaderCompressedSelection.java         |   2 -
 .../runtime/compress/workload/AWTreeNode.java      |   6 +-
 .../apache/sysds/runtime/compress/workload/Op.java |  33 +-
 .../runtime/compress/workload/OpDecompressing.java |  39 ---
 .../runtime/compress/workload/OpMetadata.java      |  15 +-
 .../sysds/runtime/compress/workload/OpNormal.java  |   5 -
 .../compress/workload/OpOverlappingDecompress.java |  38 ---
 .../sysds/runtime/compress/workload/OpSided.java   |  15 +-
 .../sysds/runtime/compress/workload/WTreeRoot.java |  31 +-
 .../compress/workload/WorkloadAnalyzer.java        | 358 +++++++++++++--------
 .../context/SparkExecutionContext.java             |  12 +-
 .../instructions/cp/SpoofCPInstruction.java        |   3 +-
 .../runtime/matrix/data/LibMatrixBincell.java      |  10 +-
 .../sysds/runtime/matrix/data/MatrixBlock.java     |  96 +++---
 .../apache/sysds/runtime/util/DataConverter.java   |   2 +-
 .../compress/AbstractCompressedUnaryTests.java     |   2 -
 .../component/compress/CompressedMatrixTest.java   | 163 +++++++++-
 .../component/compress/CompressedTestBase.java     |   9 +
 .../component/compress/workload/WorkloadTest.java  |  43 +--
 .../test/component/frame/DataCorruptionTest.java   |   8 +-
 .../test/functions/codegen/RowAggTmplTest.java     |   6 +-
 .../functions/compress/CompressInstruction.java    |   1 -
 .../compress/CompressInstructionRewrite.java       |  19 +-
 .../functions/compress/CompressRewriteSpark.java   |  43 ++-
 .../compress/configuration/CompressBase.java       |  16 +-
 .../compress/configuration/CompressCost.java       |  70 ----
 .../compress/configuration/CompressForce.java      |  36 +++
 .../compress/configuration/CompressLossy.java      |  52 ---
 .../compress/configuration/CompressLossyCost.java  |  52 ---
 .../compress/workload/WorkloadAlgorithmTest.java   |  12 +-
 .../compress/workload/WorkloadAnalysisTest.java    |   9 +-
 .../rewrite/RewriteMMCBindZeroVector.java          |  36 ++-
 src/test/resources/component/compress/1-1_y.csv    |   1 +
 .../resources/component/compress/1-1_y.csv.mtd     |   8 +
 src/test/resources/component/compress/README.md    |   2 +-
 .../compress/workload/functions/l2svm_Y.dml}       |  10 +-
 .../functions/compress/compress_mmr_sum.dml        |   2 +-
 ...press_mmr_sum.dml => compress_mmr_sum_plus.dml} |   2 +-
 ...ess_mmr_sum.dml => compress_mmr_sum_plus_2.dml} |   2 +-
 .../WorkloadAnalysisL2SVM.dml}                     |  29 +-
 71 files changed, 1122 insertions(+), 874 deletions(-)

diff --git a/src/main/java/org/apache/sysds/hops/OptimizerUtils.java b/src/main/java/org/apache/sysds/hops/OptimizerUtils.java
index d63b2cb..be916d9 100644
--- a/src/main/java/org/apache/sysds/hops/OptimizerUtils.java
+++ b/src/main/java/org/apache/sysds/hops/OptimizerUtils.java
@@ -1139,6 +1139,9 @@ public class OptimizerUtils
 		// default is worst-case estimate for robustness
 		double ret = 1.0;
 		
+		if(op == null) // If Unknown op, assume the worst
+			return ret;
+
 		if( worstcase )
 		{
 			//NOTE: for matrix-scalar operations this estimate is too conservative, because 
diff --git a/src/main/java/org/apache/sysds/hops/estim/EstimatorDensityMap.java b/src/main/java/org/apache/sysds/hops/estim/EstimatorDensityMap.java
index 9b7169e..65a8463 100644
--- a/src/main/java/org/apache/sysds/hops/estim/EstimatorDensityMap.java
+++ b/src/main/java/org/apache/sysds/hops/estim/EstimatorDensityMap.java
@@ -234,7 +234,7 @@ public class EstimatorDensityMap extends SparsityEstimator
 			_map = init(in);
 			_scaled = false;
 			if( !isPow2(_b) )
-				System.out.println("WARN: Invalid block size: "+_b);
+				LOG.warn("Invalid block size: "+_b);
 		}
 		
 		public DensityMap(MatrixBlock map, int rlenOrig, int clenOrig, int b, boolean scaled) {
@@ -244,7 +244,7 @@ public class EstimatorDensityMap extends SparsityEstimator
 			_map = map;
 			_scaled = scaled;
 			if( !isPow2(_b) )
-				System.out.println("WARN: Invalid block size: "+_b);
+				LOG.warn("Invalid block size: "+_b);
 		}
 		
 		public MatrixBlock getMap() {
diff --git a/src/main/java/org/apache/sysds/hops/ipa/IPAPassCompressionWorkloadAnalysis.java b/src/main/java/org/apache/sysds/hops/ipa/IPAPassCompressionWorkloadAnalysis.java
index b23397f..11c3ad6 100644
--- a/src/main/java/org/apache/sysds/hops/ipa/IPAPassCompressionWorkloadAnalysis.java
+++ b/src/main/java/org/apache/sysds/hops/ipa/IPAPassCompressionWorkloadAnalysis.java
@@ -24,7 +24,6 @@ import java.util.Map.Entry;
 
 import org.apache.sysds.conf.ConfigurationManager;
 import org.apache.sysds.conf.DMLConfig;
-import org.apache.sysds.hops.Hop;
 import org.apache.sysds.hops.OptimizerUtils;
 import org.apache.sysds.lops.Compression.CompressConfig;
 import org.apache.sysds.parser.DMLProgram;
@@ -54,18 +53,19 @@ public class IPAPassCompressionWorkloadAnalysis extends IPAPass {
 		Map<Long, WTreeRoot> map = WorkloadAnalyzer.getAllCandidateWorkloads(prog);
 
 		// Add compression instruction to all remaining locations
-		for(Entry<Long, WTreeRoot> e : map.entrySet()){
-			WTreeRoot tree = e.getValue();
-			CostEstimatorBuilder b = new CostEstimatorBuilder(tree);
-			// filter out compression plans that is known bad
-			
-			if(b.shouldTryToCompress()){
+		for(Entry<Long, WTreeRoot> e : map.entrySet()) {
+			final WTreeRoot tree = e.getValue();
+			final CostEstimatorBuilder b = new CostEstimatorBuilder(tree);
+			final boolean shouldCompress = b.shouldTryToCompress();
+			if(LOG.isTraceEnabled())
+				LOG.trace("IPAPass Should Compress:\n" + tree + "\n" + b + "\n Should Compress: " + shouldCompress);
+
+			// Filter out compression plans that is known to be bad
+			if(shouldCompress) 
 				tree.getRoot().setRequiresCompression(tree);
-				for(Hop h : tree.getDecompressList())
-					h.setRequiresDeCompression();
-			}
+
 		}
-		
+
 		return map != null;
 	}
 }
diff --git a/src/main/java/org/apache/sysds/hops/rewrite/RewriteAlgebraicSimplificationDynamic.java b/src/main/java/org/apache/sysds/hops/rewrite/RewriteAlgebraicSimplificationDynamic.java
index 0b91e5d..d0b1ac5 100644
--- a/src/main/java/org/apache/sysds/hops/rewrite/RewriteAlgebraicSimplificationDynamic.java
+++ b/src/main/java/org/apache/sysds/hops/rewrite/RewriteAlgebraicSimplificationDynamic.java
@@ -2801,22 +2801,26 @@ public class RewriteAlgebraicSimplificationDynamic extends HopRewriteRule
 
 		// cbind((X %*% Y), matrix(0, nrow(X), 1)) ->
 		// X %*% (cbind(Y, matrix(0, nrow(Y), 1)))
-		// if nRows of x is larger than nCols of y
+		// if nRows of x is larger than nRows of y
 		// rewrite used in MLogReg first level loop.
-		
+
 		if(HopRewriteUtils.isBinary(hi, OpOp2.CBIND) && HopRewriteUtils.isMatrixMultiply(hi.getInput(0)) &&
-			HopRewriteUtils.isDataGenOpWithConstantValue(hi.getInput(1), 0) && hi.getDim1() > hi.getDim2() * 2) {
-			final Hop oldGen = hi.getInput(1);
+			HopRewriteUtils.isDataGenOpWithConstantValue(hi.getInput(1), 0) && hi.getInput(0).getInput(0).dimsKnown() &&
+			hi.getInput(0).getInput(1).dimsKnown()) {
 			final Hop y = hi.getInput(0).getInput(1);
 			final Hop x = hi.getInput(0).getInput(0);
-			final Hop newGen = HopRewriteUtils.createDataGenOp(y, oldGen, 0);
-			final Hop newCBind = HopRewriteUtils.createBinary(y, newGen, OpOp2.CBIND);
-			final Hop newMM = HopRewriteUtils.createMatrixMultiply(x, newCBind);
-
-			HopRewriteUtils.replaceChildReference(parent, hi, newMM, pos);
-			LOG.debug("Applied MMCBind Zero algebraic simplification (line " +hi.getBeginLine()+")." );
-			return newMM;
+			final long m = x.getDim1(); // number of rows in output or X
+			final long n = y.getDim1(); // number of rows in Y or common dimension
+			if(m > n * 2) {
+				final Hop oldGen = hi.getInput(1);
+				final Hop newGen = HopRewriteUtils.createDataGenOp(y, oldGen, 0);
+				final Hop newCBind = HopRewriteUtils.createBinary(y, newGen, OpOp2.CBIND);
+				final Hop newMM = HopRewriteUtils.createMatrixMultiply(x, newCBind);
 
+				HopRewriteUtils.replaceChildReference(parent, hi, newMM, pos);
+				LOG.debug("Applied MMCBind Zero algebraic simplification (line " + hi.getBeginLine() + ").");
+				return newMM;
+			}
 		}
 		return hi;
 	}
diff --git a/src/main/java/org/apache/sysds/hops/rewrite/RewriteCompressedReblock.java b/src/main/java/org/apache/sysds/hops/rewrite/RewriteCompressedReblock.java
index 2f0f1f6c..96e1469 100644
--- a/src/main/java/org/apache/sysds/hops/rewrite/RewriteCompressedReblock.java
+++ b/src/main/java/org/apache/sysds/hops/rewrite/RewriteCompressedReblock.java
@@ -128,7 +128,11 @@ public class RewriteCompressedReblock extends StatementBlockRewriteRule {
 
 	public static boolean satisfiesSizeConstraintsForCompression(Hop hop) {
 		if(hop.getDim2() >= 1) {
-			return (hop.getDim1() >= 1000 && hop.getDim2() < 100) || hop.getDim1() / hop.getDim2() >= 75 || (hop.getSparsity() < 0.0001 && hop.getDim1() > 1000);
+			return 
+				// If number of rows is above 1000 and either very sparse or number of columns is less than 100.
+				(hop.getDim1() >= 1000 && (hop.getDim2() < 100) || hop.getSparsity() < 0.0001)
+				// If relative ratio between number of rows and columns is better than 75, aka 75 rows per one column.
+				|| hop.getDim1() / hop.getDim2() >= 75;
 		}
 		return false;
 	}
diff --git a/src/main/java/org/apache/sysds/runtime/compress/CompressedMatrixBlock.java b/src/main/java/org/apache/sysds/runtime/compress/CompressedMatrixBlock.java
index 5dcc406..bff9a21 100644
--- a/src/main/java/org/apache/sysds/runtime/compress/CompressedMatrixBlock.java
+++ b/src/main/java/org/apache/sysds/runtime/compress/CompressedMatrixBlock.java
@@ -27,6 +27,7 @@ import java.io.ObjectOutput;
 import java.lang.ref.SoftReference;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Comparator;
 import java.util.Iterator;
 import java.util.List;
 import java.util.concurrent.Callable;
@@ -71,8 +72,11 @@ import org.apache.sysds.runtime.functionobjects.Builtin.BuiltinCode;
 import org.apache.sysds.runtime.functionobjects.KahanPlus;
 import org.apache.sysds.runtime.functionobjects.KahanPlusSq;
 import org.apache.sysds.runtime.functionobjects.Mean;
+import org.apache.sysds.runtime.functionobjects.MinusMultiply;
 import org.apache.sysds.runtime.functionobjects.Multiply;
+import org.apache.sysds.runtime.functionobjects.PlusMultiply;
 import org.apache.sysds.runtime.functionobjects.SwapIndex;
+import org.apache.sysds.runtime.functionobjects.TernaryValueFunction.ValueFunctionWithConstant;
 import org.apache.sysds.runtime.instructions.InstructionUtils;
 import org.apache.sysds.runtime.instructions.cp.CM_COV_Object;
 import org.apache.sysds.runtime.instructions.cp.ScalarObject;
@@ -82,6 +86,7 @@ import org.apache.sysds.runtime.matrix.data.IJV;
 import org.apache.sysds.runtime.matrix.data.LibMatrixBincell;
 import org.apache.sysds.runtime.matrix.data.LibMatrixDatagen;
 import org.apache.sysds.runtime.matrix.data.LibMatrixReorg;
+import org.apache.sysds.runtime.matrix.data.LibMatrixTercell;
 import org.apache.sysds.runtime.matrix.data.MatrixBlock;
 import org.apache.sysds.runtime.matrix.data.MatrixIndexes;
 import org.apache.sysds.runtime.matrix.data.MatrixValue;
@@ -245,6 +250,11 @@ public class CompressedMatrixBlock extends MatrixBlock {
 
 		ret.allocateDenseBlock();
 
+		if(isOverlapping()){
+			Comparator<AColGroup> comp = Comparator.comparing(x -> effect(x));
+			_colGroups.sort(comp);
+		}
+
 		if(k == 1)
 			decompress(ret);
 		else
@@ -265,6 +275,10 @@ public class CompressedMatrixBlock extends MatrixBlock {
 		return ret;
 	}
 
+	private double effect(AColGroup x){
+		return - Math.max(x.getMax(), Math.abs(x.getMin()));
+	}
+
 	private MatrixBlock decompress(MatrixBlock ret) {
 
 		ret.setNonZeros(nonZeros == -1 && !this.isOverlapping() ? recomputeNonZeros() : nonZeros);
@@ -303,7 +317,12 @@ public class CompressedMatrixBlock extends MatrixBlock {
 	}
 
 	/**
-	 * Get the cached decompressed matrix (if it exists otherwise null)
+	 * Get the cached decompressed matrix (if it exists otherwise null).
+	 * 
+	 * This in practice means that if some other instruction have materialized the decompressed version it can be
+	 * accessed though this method with a guarantee that it did not go through the entire decompression phase.
+	 * 
+	 * @return The cached decompressed matrix, if it does not exist return null
 	 */
 	public MatrixBlock getCachedDecompressed() {
 		if(decompressedVersion != null) {
@@ -457,14 +476,15 @@ public class CompressedMatrixBlock extends MatrixBlock {
 	@Override
 	public void write(DataOutput out) throws IOException {
 		if(getExactSizeOnDisk() > MatrixBlock.estimateSizeOnDisk(rlen, clen, nonZeros)) {
-			// decompress and make a uncompressed column group. this is then used for the serialization, since it is
-			// smaller.
-			// throw new NotImplementedException("Decompressing serialization is not implemented");
-
-			MatrixBlock uncompressed = getUncompressed("Decompressing serialization for smaller serialization");
+			// If the size of this matrixBlock is smaller in uncompressed format, then
+			// decompress and save inside an uncompressed column group.
+			MatrixBlock uncompressed = getUncompressed("for smaller serialization");
 			ColGroupUncompressed cg = new ColGroupUncompressed(uncompressed);
 			allocateColGroup(cg);
 			nonZeros = cg.getNumberNonZeros();
+			// clear the soft reference to the decompressed version, since the one column group is perfectly,
+			// representing the decompressed version.
+			decompressedVersion = null;
 		}
 		// serialize compressed matrix block
 		out.writeInt(rlen);
@@ -651,11 +671,13 @@ public class CompressedMatrixBlock extends MatrixBlock {
 
 		if(transposeOutput) {
 			ReorgOperator r_op = new ReorgOperator(SwapIndex.getSwapIndexFnObject(), op.getNumThreads());
-			return ret.reorgOperations(r_op, new MatrixBlock(), 0, 0, 0);
+			ret = ret.reorgOperations(r_op, new MatrixBlock(), 0, 0, 0);
 		}
-		else
-			return ret;
-
+		
+		if(ret.getNumRows() == 0 || ret.getNumColumns() == 0)
+			throw new DMLCompressionException("Error in outputted MM no dimensions");
+		
+		return ret;
 	}
 
 	private MatrixBlock doubleCompressedAggregateBinaryOperations(CompressedMatrixBlock m1, CompressedMatrixBlock m2,
@@ -667,7 +689,6 @@ public class CompressedMatrixBlock extends MatrixBlock {
 			return aggregateBinaryOperations(m1, getUncompressed(m2), ret, op, transposeLeft, transposeRight);
 		}
 		else if(transposeLeft && !transposeRight) {
-			// Select witch compressed matrix to decompress.
 			if(m1.getNumColumns() > m2.getNumColumns()) {
 				ret = CLALibLeftMultBy.leftMultByMatrixTransposed(m1, m2, ret, op.getNumThreads());
 				ReorgOperator r_op = new ReorgOperator(SwapIndex.getSwapIndexFnObject(), op.getNumThreads());
@@ -1099,10 +1120,13 @@ public class CompressedMatrixBlock extends MatrixBlock {
 		printDecompressWarning("aggregateTernaryOperations " + op.aggOp.getClass().getSimpleName() + " "
 			+ op.indexFn.getClass().getSimpleName() + " " + op.aggOp.increOp.fn.getClass().getSimpleName() + " "
 			+ op.binaryFn.getClass().getSimpleName() + " m1,m2,m3 " + m1C + " " + m2C + " " + m3C);
-		MatrixBlock left = getUncompressed();
+		MatrixBlock left = getUncompressed(m1);
 		MatrixBlock right1 = getUncompressed(m2);
 		MatrixBlock right2 = getUncompressed(m3);
-		return left.aggregateTernaryOperations(left, right1, right2, ret, op, inCP);
+		ret = left.aggregateTernaryOperations(left, right1, right2, ret, op, inCP);
+		if(ret.getNumRows() == 0 || ret.getNumColumns() == 0)
+			throw new DMLCompressionException("Invalid output");
+		return ret;
 	}
 
 	@Override
@@ -1184,10 +1208,54 @@ public class CompressedMatrixBlock extends MatrixBlock {
 
 	@Override
 	public MatrixBlock ternaryOperations(TernaryOperator op, MatrixBlock m2, MatrixBlock m3, MatrixBlock ret) {
-		MatrixBlock left = getUncompressed("ternaryOperations  " + op.fn);
-		MatrixBlock right1 = getUncompressed(m2);
-		MatrixBlock right2 = getUncompressed(m3);
-		return left.ternaryOperations(op, right1, right2, ret);
+
+		// prepare inputs
+		final int r1 = getNumRows();
+		final int r2 = m2.getNumRows();
+		final int r3 = m3.getNumRows();
+		final int c1 = getNumColumns();
+		final int c2 = m2.getNumColumns();
+		final int c3 = m3.getNumColumns();
+		final boolean s1 = (r1 == 1 && c1 == 1);
+		final boolean s2 = (r2 == 1 && c2 == 1);
+		final boolean s3 = (r3 == 1 && c3 == 1);
+		final double d1 = s1 ? quickGetValue(0, 0) : Double.NaN;
+		final double d2 = s2 ? m2.quickGetValue(0, 0) : Double.NaN;
+		final double d3 = s3 ? m3.quickGetValue(0, 0) : Double.NaN;
+		final int m = Math.max(Math.max(r1, r2), r3);
+		final int n = Math.max(Math.max(c1, c2), c3);
+
+		ternaryOperationCheck(s1, s2, s3, m, r1, r2, r3, n, c1, c2, c3);
+
+		final boolean PM_Or_MM = (op.fn instanceof PlusMultiply || op.fn instanceof MinusMultiply);
+		if(PM_Or_MM && ((s2 && d2 == 0) || (s3 && d3 == 0))) {
+			ret = new CompressedMatrixBlock();
+			ret.copy(this);
+			return ret;
+		}
+
+		if(m2 instanceof CompressedMatrixBlock)
+			m2 = ((CompressedMatrixBlock) m2)
+				.getUncompressed("Ternay Operator arg2 " + op.fn.getClass().getSimpleName());
+		if(m3 instanceof CompressedMatrixBlock)
+			m3 = ((CompressedMatrixBlock) m3)
+				.getUncompressed("Ternay Operator arg3 " + op.fn.getClass().getSimpleName());
+
+		if(s2 != s3 && (op.fn instanceof PlusMultiply || op.fn instanceof MinusMultiply)) {
+			// SPECIAL CASE for sparse-dense combinations of common +* and -*
+			BinaryOperator bop = ((ValueFunctionWithConstant) op.fn).setOp2Constant(s2 ? d2 : d3);
+			ret = CLALibBinaryCellOp.binaryOperations(bop, this, s2 ? m3 : m2, ret);
+		}
+		else {
+			final boolean sparseOutput = evalSparseFormatInMemory(m, n,
+				(s1 ? m * n * (d1 != 0 ? 1 : 0) : getNonZeros()) +
+					Math.min(s2 ? m * n : m2.getNonZeros(), s3 ? m * n : m3.getNonZeros()));
+			ret.reset(m, n, sparseOutput);
+			final MatrixBlock thisUncompressed = getUncompressed("Ternary Operation not supported");
+			LibMatrixTercell.tercellOp(thisUncompressed, m2, m3, ret, op);
+			ret.examSparsity();
+		}
+		return ret;
 	}
 
 	@Override
@@ -1240,19 +1308,22 @@ public class CompressedMatrixBlock extends MatrixBlock {
 	}
 
 	public MatrixBlock getUncompressed(String operation) {
+		MatrixBlock d_compressed = getCachedDecompressed();
+		if(d_compressed != null)
+			return d_compressed;
+		if(isEmpty())
+			return new MatrixBlock(getNumRows(), getNumColumns(), true);
 		printDecompressWarning(operation);
 		return getUncompressed();
 	}
 
 	private static void printDecompressWarning(String operation) {
-		LOG.warn("Operation '" + operation + "' not supported yet - decompressing for ULA operations.");
+		LOG.warn("Decompressing because: " + operation);
 	}
 
 	private static void printDecompressWarning(String operation, MatrixBlock m2) {
 		if(isCompressed(m2))
-			LOG.warn("Operation '" + operation + "' not supported yet - decompressing for ULA operations.");
-		else
-			LOG.warn("Operation '" + operation + "' not supported yet - decompressing'");
+			printDecompressWarning(operation);
 	}
 
 	@Override
@@ -1300,13 +1371,13 @@ public class CompressedMatrixBlock extends MatrixBlock {
 	}
 
 	private void copyCompressedMatrix(CompressedMatrixBlock that) {
-		this.rlen = that.rlen;
-		this.clen = that.clen;
+		this.rlen = that.getNumRows();
+		this.clen = that.getNumColumns();
 		this.sparseBlock = null;
 		this.denseBlock = null;
 		this.nonZeros = that.getNonZeros();
 
-		this._colGroups = new ArrayList<>();
+		this._colGroups = new ArrayList<>(that.getColGroups().size());
 		for(AColGroup cg : that._colGroups)
 			_colGroups.add(cg.copy());
 
diff --git a/src/main/java/org/apache/sysds/runtime/compress/CompressedMatrixBlockFactory.java b/src/main/java/org/apache/sysds/runtime/compress/CompressedMatrixBlockFactory.java
index 5f45d56..98567e0 100644
--- a/src/main/java/org/apache/sysds/runtime/compress/CompressedMatrixBlockFactory.java
+++ b/src/main/java/org/apache/sysds/runtime/compress/CompressedMatrixBlockFactory.java
@@ -185,6 +185,9 @@ public class CompressedMatrixBlockFactory {
 		AColGroup cg = ColGroupFactory.genColGroupConst(numRows, numCols, value);
 		block.allocateColGroup(cg);
 		block.recomputeNonZeros();
+		if(block.getNumRows() == 0 || block.getNumColumns() == 0) {
+			throw new DMLCompressionException("Invalid size of allocated constant compressed matrix block");
+		}
 		return block;
 	}
 
@@ -238,14 +241,17 @@ public class CompressedMatrixBlockFactory {
 		_stats.estimatedSizeCols = sizeInfos.memoryEstimate();
 		logPhase();
 
+		final double sizeToCompare = (costEstimator instanceof ComputationCostEstimator &&
+			((ComputationCostEstimator) costEstimator).isDense()) ? _stats.denseSize : _stats.originalSize;
+
 		final boolean isValidForComputeBasedCompression = isComputeBasedCompression() &&
 			(compSettings.minimumCompressionRatio != 1.0) ? _stats.estimatedSizeCols *
-				compSettings.minimumCompressionRatio < _stats.originalSize : true;
+				compSettings.minimumCompressionRatio < sizeToCompare : true;
 		final boolean isValidForMemoryBasedCompression = _stats.estimatedSizeCols *
-			compSettings.minimumCompressionRatio < _stats.originalSize;
+			compSettings.minimumCompressionRatio < sizeToCompare;
 
 		if(isValidForComputeBasedCompression || isValidForMemoryBasedCompression)
-			coCodePhase(sizeEstimator, sizeInfos, costEstimator);
+			coCodePhase(sizeEstimator, sizeInfos, costEstimator, sizeToCompare);
 		else {
 			LOG.info("Estimated Size of singleColGroups: " + _stats.estimatedSizeCols);
 			LOG.info("Original size                    : " + _stats.originalSize);
@@ -257,7 +263,7 @@ public class CompressedMatrixBlockFactory {
 	}
 
 	private void coCodePhase(CompressedSizeEstimator sizeEstimator, CompressedSizeInfo sizeInfos,
-		ICostEstimate costEstimator) {
+		ICostEstimate costEstimator, double sizeToCompare) {
 		coCodeColGroups = CoCoderFactory.findCoCodesByPartitioning(sizeEstimator, sizeInfos, k, costEstimator,
 			compSettings);
 
@@ -267,7 +273,7 @@ public class CompressedMatrixBlockFactory {
 
 		// if cocode is estimated larger than uncompressed abort compression.
 		if(isComputeBasedCompression() &&
-			_stats.estimatedSizeCoCoded * compSettings.minimumCompressionRatio > _stats.originalSize) {
+			_stats.estimatedSizeCoCoded * compSettings.minimumCompressionRatio > sizeToCompare) {
 
 			coCodeColGroups = null;
 			LOG.info("Aborting compression because the cocoded size : " + _stats.estimatedSizeCoCoded);
@@ -281,7 +287,7 @@ public class CompressedMatrixBlockFactory {
 		final int numRows = mb.getNumRows();
 		final long nnz = mb.getNonZeros();
 		final int colGroupSize = 100;
-		if(nnz == numRows) {
+		if(nnz == numRows && numColumns != 1) {
 			boolean onlyOneValues = true;
 			LOG.debug("Looks like one hot encoded.");
 			if(mb.isInSparseFormat()) {
diff --git a/src/main/java/org/apache/sysds/runtime/compress/CompressionSettings.java b/src/main/java/org/apache/sysds/runtime/compress/CompressionSettings.java
index ea04e8e..b347031 100644
--- a/src/main/java/org/apache/sysds/runtime/compress/CompressionSettings.java
+++ b/src/main/java/org/apache/sysds/runtime/compress/CompressionSettings.java
@@ -108,10 +108,10 @@ public class CompressionSettings {
 	 */
 	public final double minimumCompressionRatio;
 
-	protected CompressionSettings(double samplingRatio, boolean allowSharedDictionary, String transposeInput,
-		 int seed, boolean lossy, EnumSet<CompressionType> validCompressions,
-		boolean sortValuesByLength, PartitionerType columnPartitioner, int maxColGroupCoCode, double coCodePercentage,
-		int minimumSampleSize, EstimationType estimationType, CostType costComputationType, double minimumCompressionRatio) {
+	protected CompressionSettings(double samplingRatio, boolean allowSharedDictionary, String transposeInput, int seed,
+		boolean lossy, EnumSet<CompressionType> validCompressions, boolean sortValuesByLength,
+		PartitionerType columnPartitioner, int maxColGroupCoCode, double coCodePercentage, int minimumSampleSize,
+		EstimationType estimationType, CostType costComputationType, double minimumCompressionRatio) {
 		this.samplingRatio = samplingRatio;
 		this.allowSharedDictionary = allowSharedDictionary;
 		this.transposeInput = transposeInput;
diff --git a/src/main/java/org/apache/sysds/runtime/compress/CompressionSettingsBuilder.java b/src/main/java/org/apache/sysds/runtime/compress/CompressionSettingsBuilder.java
index 2864118..156fdfc 100644
--- a/src/main/java/org/apache/sysds/runtime/compress/CompressionSettingsBuilder.java
+++ b/src/main/java/org/apache/sysds/runtime/compress/CompressionSettingsBuilder.java
@@ -268,7 +268,7 @@ public class CompressionSettingsBuilder {
 		return this;
 	}
 
-	public CompressionSettingsBuilder setMinimumCompressionRatio(double ratio){
+	public CompressionSettingsBuilder setMinimumCompressionRatio(double ratio) {
 		this.minimumCompressionRatio = ratio;
 		return this;
 	}
@@ -281,6 +281,6 @@ public class CompressionSettingsBuilder {
 	public CompressionSettings create() {
 		return new CompressionSettings(samplingRatio, allowSharedDictionary, transposeInput, seed, lossy,
 			validCompressions, sortValuesByLength, columnPartitioner, maxColGroupCoCode, coCodePercentage,
-			minimumSampleSize, estimationType, costType,minimumCompressionRatio);
+			minimumSampleSize, estimationType, costType, minimumCompressionRatio);
 	}
 }
diff --git a/src/main/java/org/apache/sysds/runtime/compress/CompressionStatistics.java b/src/main/java/org/apache/sysds/runtime/compress/CompressionStatistics.java
index 0ad1900..63b579c 100644
--- a/src/main/java/org/apache/sysds/runtime/compress/CompressionStatistics.java
+++ b/src/main/java/org/apache/sysds/runtime/compress/CompressionStatistics.java
@@ -97,7 +97,7 @@ public class CompressionStatistics {
 		return size == 0.0 ? Double.POSITIVE_INFINITY : (double) originalSize / size;
 	}
 
-	public double getDenseRatio(){
+	public double getDenseRatio() {
 		return size == 0.0 ? Double.POSITIVE_INFINITY : (double) denseSize / size;
 	}
 
@@ -109,7 +109,7 @@ public class CompressionStatistics {
 		sb.append("\nOriginal Size         : " + originalSize);
 		sb.append("\nCompressed Size       : " + size);
 		sb.append("\nCompressionRatio      : " + getRatio());
-		if(colGroupCounts != null){
+		if(colGroupCounts != null) {
 			sb.append("\nCompressionTypes      : " + getGroupsTypesString());
 			sb.append("\nCompressionGroupSizes : " + getGroupsSizesString());
 		}
diff --git a/src/main/java/org/apache/sysds/runtime/compress/DMLCompressionException.java b/src/main/java/org/apache/sysds/runtime/compress/DMLCompressionException.java
index 4761e5e..bc95246 100644
--- a/src/main/java/org/apache/sysds/runtime/compress/DMLCompressionException.java
+++ b/src/main/java/org/apache/sysds/runtime/compress/DMLCompressionException.java
@@ -21,22 +21,22 @@ package org.apache.sysds.runtime.compress;
 
 import org.apache.sysds.runtime.DMLRuntimeException;
 
-public class DMLCompressionException extends DMLRuntimeException{
+public class DMLCompressionException extends DMLRuntimeException {
 	private static final long serialVersionUID = 1L;
 
-	public DMLCompressionException(){
+	public DMLCompressionException() {
 		super("Invalid execution on Compressed MatrixBlock");
 	}
 
 	public DMLCompressionException(String string) {
 		super(string);
 	}
-	
+
 	public DMLCompressionException(Exception e) {
 		super(e);
 	}
 
-	public DMLCompressionException(String string, Exception ex){
-		super(string,ex);
+	public DMLCompressionException(String string, Exception ex) {
+		super(string, ex);
 	}
-}
\ No newline at end of file
+}
diff --git a/src/main/java/org/apache/sysds/runtime/compress/cocode/CoCodeGreedy.java b/src/main/java/org/apache/sysds/runtime/compress/cocode/CoCodeGreedy.java
index 3091ba0..cf366e7 100644
--- a/src/main/java/org/apache/sysds/runtime/compress/cocode/CoCodeGreedy.java
+++ b/src/main/java/org/apache/sysds/runtime/compress/cocode/CoCodeGreedy.java
@@ -108,8 +108,8 @@ public class CoCodeGreedy extends AColumnCoCoder {
 			else
 				break;
 		}
-
-		LOG.debug(mem.stats());
+		if(LOG.isDebugEnabled())
+			LOG.debug("Memorizer stats:" + mem.stats());
 		mem.resetStats();
 
 		List<CompressedSizeInfoColGroup> ret = new ArrayList<>(workset.size());
@@ -132,10 +132,6 @@ public class CoCodeGreedy extends AColumnCoCoder {
 			mem.put(new ColIndexes(g.getColumns()), g);
 		}
 
-		// public CompressedSizeInfoColGroup get(CompressedSizeInfoColGroup g) {
-		// 	return mem.get(new ColIndexes(g.getColumns()));
-		// }
-
 		public CompressedSizeInfoColGroup get(ColIndexes c) {
 			return mem.get(c);
 		}
diff --git a/src/main/java/org/apache/sysds/runtime/compress/colgroup/ColGroupFactory.java b/src/main/java/org/apache/sysds/runtime/compress/colgroup/ColGroupFactory.java
index 9416618..d8b85c1 100644
--- a/src/main/java/org/apache/sysds/runtime/compress/colgroup/ColGroupFactory.java
+++ b/src/main/java/org/apache/sysds/runtime/compress/colgroup/ColGroupFactory.java
@@ -458,7 +458,9 @@ public final class ColGroupFactory {
 	}
 
 	public static AColGroup genColGroupConst(int numRows, int numCols, double value) {
-
+		if(numRows <= 0 || numCols <= 0)
+			throw new DMLCompressionException(
+				"Invalid construction of constant column group with rows/cols: " + numRows + "/" + numCols);
 		int[] colIndices = new int[numCols];
 		for(int i = 0; i < numCols; i++)
 			colIndices[i] = i;
diff --git a/src/main/java/org/apache/sysds/runtime/compress/colgroup/ColGroupUncompressed.java b/src/main/java/org/apache/sysds/runtime/compress/colgroup/ColGroupUncompressed.java
index b1b0540..35ba409 100644
--- a/src/main/java/org/apache/sysds/runtime/compress/colgroup/ColGroupUncompressed.java
+++ b/src/main/java/org/apache/sysds/runtime/compress/colgroup/ColGroupUncompressed.java
@@ -142,9 +142,9 @@ public class ColGroupUncompressed extends AColGroup {
 		_data = data;
 	}
 
-	private static int[] generateColumnList(int nCol){
+	private static int[] generateColumnList(int nCol) {
 		int[] cols = new int[nCol];
-		for(int i = 0; i< nCol; i++)
+		for(int i = 0; i < nCol; i++)
 			cols[i] = i;
 		return cols;
 	}
@@ -456,7 +456,6 @@ public class ColGroupUncompressed extends AColGroup {
 	@Override
 	public AColGroup copy() {
 		MatrixBlock newData = new MatrixBlock(_data.getNumRows(), _data.getNumColumns(), _data.isInSparseFormat());
-		// _data.copy(newData);
 		newData.copy(_data);
 		return new ColGroupUncompressed(_colIndexes, newData);
 	}
@@ -640,7 +639,6 @@ public class ColGroupUncompressed extends AColGroup {
 
 	@Override
 	public void computeColSums(double[] c) {
-		// TODO Auto-generated method stub
 		MatrixBlock colSum = _data.colSum();
 		if(colSum.isInSparseFormat()) {
 			throw new NotImplementedException();
@@ -649,7 +647,6 @@ public class ColGroupUncompressed extends AColGroup {
 			double[] dv = colSum.getDenseBlockValues();
 			for(int i = 0; i < _colIndexes.length; i++)
 				c[_colIndexes[i]] += dv[i];
-
 		}
 	}
 }
diff --git a/src/main/java/org/apache/sysds/runtime/compress/colgroup/ColGroupValue.java b/src/main/java/org/apache/sysds/runtime/compress/colgroup/ColGroupValue.java
index 6844095..c931880 100644
--- a/src/main/java/org/apache/sysds/runtime/compress/colgroup/ColGroupValue.java
+++ b/src/main/java/org/apache/sysds/runtime/compress/colgroup/ColGroupValue.java
@@ -896,8 +896,6 @@ public abstract class ColGroupValue extends ColGroupCompressed implements Clonea
 		}
 	}
 
-	private static boolean logMM = true;
-
 	/**
 	 * Matrix Multiply the two matrices, note that the left side is transposed,
 	 * 
@@ -978,10 +976,6 @@ public abstract class ColGroupValue extends ColGroupCompressed implements Clonea
 
 		}
 		catch(Exception e) {
-			if(logMM) {
-				LOG.error("\nLeft (transposed):\n" + left + "\nRight:\n" + right);
-				logMM = false;
-			}
 			throw new DMLCompressionException("MM of pre aggregated colGroups failed", e);
 		}
 	}
diff --git a/src/main/java/org/apache/sysds/runtime/compress/colgroup/mapping/MapToFactory.java b/src/main/java/org/apache/sysds/runtime/compress/colgroup/mapping/MapToFactory.java
index 6c0b9fa..63fecc5 100644
--- a/src/main/java/org/apache/sysds/runtime/compress/colgroup/mapping/MapToFactory.java
+++ b/src/main/java/org/apache/sysds/runtime/compress/colgroup/mapping/MapToFactory.java
@@ -109,12 +109,13 @@ public final class MapToFactory {
 		final int nVR = right.getUnique();
 		final int size = left.size();
 		final long maxUnique = nVL * nVR;
-		if(maxUnique > (long)Integer.MAX_VALUE)
-			throw new DMLCompressionException("Joining impossible using linearized join, since each side has a large number of unique values");
+		if(maxUnique > (long) Integer.MAX_VALUE)
+			throw new DMLCompressionException(
+				"Joining impossible using linearized join, since each side has a large number of unique values");
 		if(size != right.size())
 			throw new DMLCompressionException("Invalid input maps to join, must contain same number of rows");
 
-		return computeJoin(left, right, size, nVL, (int)maxUnique);
+		return computeJoin(left, right, size, nVL, (int) maxUnique);
 	}
 
 	private static AMapToData computeJoin(AMapToData left, AMapToData right, int size, int nVL, int maxUnique) {
@@ -133,11 +134,11 @@ public final class MapToFactory {
 				tmp.set(i, newUID - 1);
 				map[nv] = newUID++;
 			}
-			else 
+			else
 				tmp.set(i, mapV - 1);
 		}
 
-		tmp.setUnique(newUID-1);
+		tmp.setUnique(newUID - 1);
 		return tmp;
 	}
 }
diff --git a/src/main/java/org/apache/sysds/runtime/compress/cost/ComputationCostEstimator.java b/src/main/java/org/apache/sysds/runtime/compress/cost/ComputationCostEstimator.java
index 8db6729..1653f51 100644
--- a/src/main/java/org/apache/sysds/runtime/compress/cost/ComputationCostEstimator.java
+++ b/src/main/java/org/apache/sysds/runtime/compress/cost/ComputationCostEstimator.java
@@ -31,7 +31,7 @@ public class ComputationCostEstimator implements ICostEstimate {
 	private final boolean _isCompareAll;
 
 	private final int _nRows;
-	// private final int _nColsInMatrix;
+	private final int _nCols;
 
 	// Iteration through each row of decompressed.
 	private final int _scans;
@@ -44,6 +44,8 @@ public class ComputationCostEstimator implements ICostEstimate {
 	// private final int _rowBasedOps;
 	private final int _dictionaryOps;
 
+	private final boolean _isDensifying;
+
 	/**
 	 * A Cost based estimator based on the WTree that is parsed in IPA.
 	 * 
@@ -51,7 +53,7 @@ public class ComputationCostEstimator implements ICostEstimate {
 	 */
 	protected ComputationCostEstimator(int nRows, int nCols, boolean compareAll, InstructionTypeCounter counts) {
 		_nRows = nRows;
-		// _nColsInMatrix = nCols;
+		_nCols = nCols;
 		_isCompareAll = compareAll;
 		_scans = counts.scans;
 		_decompressions = counts.decompressions;
@@ -60,11 +62,31 @@ public class ComputationCostEstimator implements ICostEstimate {
 		_compressedMultiplication = counts.compressedMultiplications;
 		_rightMultiplications = counts.rightMultiplications;
 		_dictionaryOps = counts.dictionaryOps;
+		_isDensifying = counts.isDensifying;
 		// _rowBasedOps = counts.rowBasedOps;
 		if(LOG.isDebugEnabled())
 			LOG.debug(this);
 	}
 
+	public ComputationCostEstimator(int nRows, int nCols, int scans, int decompressions, int overlappingDecompressions,
+		int leftMultiplictions, int compressedMultiplication, int rightMultiplications, int dictioanaryOps, boolean isDensifying) {
+		_nRows = nRows;
+		_nCols = nCols;
+		_isCompareAll = false;
+		_scans = scans;
+		_decompressions = decompressions;
+		_overlappingDecompressions = overlappingDecompressions;
+		_leftMultiplications = leftMultiplictions;
+		_compressedMultiplication = compressedMultiplication;
+		_rightMultiplications = rightMultiplications;
+		_dictionaryOps = dictioanaryOps;
+		_isDensifying = isDensifying;
+	}
+
+	public static ComputationCostEstimator genDefaultCostCase(int nRows, int nCols){
+		return new ComputationCostEstimator(nRows,nCols, 1, 1, 0, 1, 1, 1, 10, true);
+	}
+
 	@Override
 	public double getUncompressedCost(int nRows, int nCols, int sparsity) {
 		throw new NotImplementedException();
@@ -84,6 +106,7 @@ public class ComputationCostEstimator implements ICostEstimate {
 		// 16 is assuming that the right side is 16 rows.
 		double rmc = rightMultCost(g) * 16;
 		cost += _rightMultiplications * rmc;
+
 		// cost += _compressedMultiplication * (lmc + rmc);
 		cost += _compressedMultiplication * _compressedMultCost(g);
 		cost += _dictionaryOps * dictionaryOpsCost(g);
@@ -110,28 +133,29 @@ public class ComputationCostEstimator implements ICostEstimate {
 	}
 
 	private double _compressedMultCost(CompressedSizeInfoColGroup g) {
-		final int nCols = g.getColumns().length;
+		final int nColsInGroup = g.getColumns().length;
 		final double mcf = g.getMostCommonFraction();
 		final double preAggregateCost = mcf > 0.6 ? _nRows * (1 - 0.7 * mcf) : _nRows;
 
 		final double numberTuples = (float) g.getNumVals();
 		final double tupleSparsity = g.getTupleSparsity();
-		final double postScalingCost = (nCols > 1 && tupleSparsity > 0.4) ? numberTuples * nCols * tupleSparsity *
-			1.4 : numberTuples * nCols;
+		final double postScalingCost = (nColsInGroup > 1 && tupleSparsity > 0.4) ? numberTuples * nColsInGroup * tupleSparsity *
+			1.4 : numberTuples * nColsInGroup;
 		if(numberTuples < 64000)
 			return preAggregateCost + postScalingCost;
 		else
 			return preAggregateCost * (numberTuples / 64000) + postScalingCost * (numberTuples / 64000);
 	}
 
-	private static double rightMultCost(CompressedSizeInfoColGroup g) {
-		final int nCols = g.getColumns().length;
+	private double rightMultCost(CompressedSizeInfoColGroup g) {
+		final int nColsInGroup = g.getColumns().length;
 		final int numberTuples = g.getNumVals() * 10;
 		final double tupleSparsity = g.getTupleSparsity();
-		final double postScalingCost = (nCols > 1 && tupleSparsity > 0.4) ? numberTuples * nCols * tupleSparsity *
-			1.4 : numberTuples * nCols;
+		final double postScalingCost = (nColsInGroup > 1 && tupleSparsity > 0.4) ? numberTuples * nColsInGroup * tupleSparsity *
+			1.4 : numberTuples * nColsInGroup;
+		final double postAllocationCost = _nCols * numberTuples;
 
-		return postScalingCost;
+		return postScalingCost + postAllocationCost;
 	}
 
 	private double decompressionCost(CompressedSizeInfoColGroup g) {
@@ -227,6 +251,10 @@ public class ComputationCostEstimator implements ICostEstimate {
 		return true;
 	}
 
+	public boolean isDense(){
+		return _isDensifying;
+	}
+
 	@Override
 	public String toString() {
 		StringBuilder sb = new StringBuilder();
diff --git a/src/main/java/org/apache/sysds/runtime/compress/cost/CostEstimatorBuilder.java b/src/main/java/org/apache/sysds/runtime/compress/cost/CostEstimatorBuilder.java
index 3d58bff..cfd22dd 100644
--- a/src/main/java/org/apache/sysds/runtime/compress/cost/CostEstimatorBuilder.java
+++ b/src/main/java/org/apache/sysds/runtime/compress/cost/CostEstimatorBuilder.java
@@ -26,10 +26,8 @@ import org.apache.commons.logging.LogFactory;
 import org.apache.sysds.hops.AggUnaryOp;
 import org.apache.sysds.hops.Hop;
 import org.apache.sysds.hops.IndexingOp;
-import org.apache.sysds.hops.ParameterizedBuiltinOp;
 import org.apache.sysds.runtime.compress.workload.Op;
 import org.apache.sysds.runtime.compress.workload.OpMetadata;
-import org.apache.sysds.runtime.compress.workload.OpOverlappingDecompress;
 import org.apache.sysds.runtime.compress.workload.OpSided;
 import org.apache.sysds.runtime.compress.workload.WTreeNode;
 import org.apache.sysds.runtime.compress.workload.WTreeRoot;
@@ -44,6 +42,8 @@ public final class CostEstimatorBuilder implements Serializable {
 
 	public CostEstimatorBuilder(WTreeRoot root) {
 		counter = new InstructionTypeCounter();
+		if(root.isDecompressing())
+			counter.decompressions++;
 		for(Op o : root.getOps())
 			addOp(1, o, counter);
 		for(WTreeNode n : root.getChildNodes())
@@ -59,9 +59,7 @@ public final class CostEstimatorBuilder implements Serializable {
 	}
 
 	private static void addNode(int count, WTreeNode n, InstructionTypeCounter counter) {
-
 		int mult = n.getReps();
-
 		for(Op o : n.getOps())
 			addOp(count * mult, o, counter);
 		for(WTreeNode nc : n.getChildNodes())
@@ -69,27 +67,29 @@ public final class CostEstimatorBuilder implements Serializable {
 	}
 
 	private static void addOp(int count, Op o, InstructionTypeCounter counter) {
+		if(o.isDecompressing()) {
+			if(o.isOverlapping())
+				counter.overlappingDecompressions += count;
+			else
+				counter.decompressions += count;
+		}
+		if(o.isDensifying()){
+			counter.isDensifying = true;
+		}
+
 		if(o instanceof OpSided) {
 			OpSided os = (OpSided) o;
 			if(os.isLeftMM())
 				counter.leftMultiplications += count;
-			else if(os.isRightMM()) {
+			else if(os.isRightMM())
 				counter.rightMultiplications += count;
-				if(os.isDecompressing())
-					counter.overlappingDecompressions += count;
-			}
 			else
 				counter.compressedMultiplications += count;
 		}
 		else if(o instanceof OpMetadata) {
 			// ignore it
 		}
-		else if(o instanceof OpOverlappingDecompress) {
-			counter.overlappingDecompressions += count;
-		}
 		else {
-			if(o.isDecompressing())
-				counter.decompressions += count;
 			Hop h = o.getHop();
 			if(h instanceof AggUnaryOp) {
 				AggUnaryOp agop = (AggUnaryOp) o.getHop();
@@ -108,12 +108,6 @@ public final class CostEstimatorBuilder implements Serializable {
 					counter.indexing++;
 				else if(idxO.isAllRows())
 					counter.dictionaryOps += count; // Technically not correct but better than decompression
-				else
-					counter.decompressions += count;
-			}
-			else if(h instanceof ParameterizedBuiltinOp) {
-				// ParameterizedBuiltinOp pop = (ParameterizedBuiltinOp) h;
-				counter.decompressions += count;
 			}
 			else
 				counter.dictionaryOps += count;
@@ -122,7 +116,7 @@ public final class CostEstimatorBuilder implements Serializable {
 
 	public boolean shouldTryToCompress() {
 		int numberOps = 0;
-		numberOps += counter.scans + counter.leftMultiplications * 2 + counter.rightMultiplications +
+		numberOps += counter.scans + counter.leftMultiplications * 2 + counter.rightMultiplications * 2 +
 			counter.compressedMultiplications * 4 + counter.dictionaryOps;
 		numberOps -= counter.decompressions + counter.overlappingDecompressions;
 
diff --git a/src/main/java/org/apache/sysds/runtime/compress/cost/CostEstimatorFactory.java b/src/main/java/org/apache/sysds/runtime/compress/cost/CostEstimatorFactory.java
index 83b794e..2e64781 100644
--- a/src/main/java/org/apache/sysds/runtime/compress/cost/CostEstimatorFactory.java
+++ b/src/main/java/org/apache/sysds/runtime/compress/cost/CostEstimatorFactory.java
@@ -38,14 +38,8 @@ public final class CostEstimatorFactory {
 				return new DistinctCostEstimator(nRows, cs);
 			case W_TREE:
 			case AUTO:
-				if(root != null) {
-					CostEstimatorBuilder b = new CostEstimatorBuilder(root);
-					if(LOG.isDebugEnabled())
-						LOG.debug(b);
-					return b.create(nRows, nCols);
-				}
-				else
-					return new MemoryCostEstimator();
+				return root != null ? new CostEstimatorBuilder(root).create(nRows, nCols) : ComputationCostEstimator
+					.genDefaultCostCase(nRows, nCols);
 			case MEMORY:
 			default:
 				return new MemoryCostEstimator();
diff --git a/src/main/java/org/apache/sysds/runtime/compress/cost/InstructionTypeCounter.java b/src/main/java/org/apache/sysds/runtime/compress/cost/InstructionTypeCounter.java
index 8c2b594..215983b 100644
--- a/src/main/java/org/apache/sysds/runtime/compress/cost/InstructionTypeCounter.java
+++ b/src/main/java/org/apache/sysds/runtime/compress/cost/InstructionTypeCounter.java
@@ -34,6 +34,8 @@ public final class InstructionTypeCounter implements Serializable {
 	protected int dictionaryOps = 0; // base cost is one pass of dictionary
 	protected int indexing = 0;
 
+	protected boolean isDensifying = false;
+
 	protected InstructionTypeCounter() {
 
 	}
diff --git a/src/main/java/org/apache/sysds/runtime/compress/estim/CompressedSizeEstimator.java b/src/main/java/org/apache/sysds/runtime/compress/estim/CompressedSizeEstimator.java
index ef7d9dd..912321c 100644
--- a/src/main/java/org/apache/sysds/runtime/compress/estim/CompressedSizeEstimator.java
+++ b/src/main/java/org/apache/sysds/runtime/compress/estim/CompressedSizeEstimator.java
@@ -189,8 +189,8 @@ public abstract class CompressedSizeEstimator {
 	 * 
 	 * if the number of distinct elements in both sides multiplied is larger than Integer, return null.
 	 * 
-	 * If either side was constructed without analysis then fall back to default materialization of double arrays.
-	 * O
+	 * If either side was constructed without analysis then fall back to default materialization of double arrays. O
+	 * 
 	 * @param g1 First group
 	 * @param g2 Second group
 	 * @return A joined compressed size estimation for the group.
diff --git a/src/main/java/org/apache/sysds/runtime/compress/estim/CompressedSizeEstimatorExact.java b/src/main/java/org/apache/sysds/runtime/compress/estim/CompressedSizeEstimatorExact.java
index 1531781..2e80532 100644
--- a/src/main/java/org/apache/sysds/runtime/compress/estim/CompressedSizeEstimatorExact.java
+++ b/src/main/java/org/apache/sysds/runtime/compress/estim/CompressedSizeEstimatorExact.java
@@ -37,7 +37,8 @@ public class CompressedSizeEstimatorExact extends CompressedSizeEstimator {
 	}
 
 	@Override
-	public CompressedSizeInfoColGroup estimateCompressedColGroupSize(int[] colIndexes, int estimate, int nrUniqueUpperBound) {
+	public CompressedSizeInfoColGroup estimateCompressedColGroupSize(int[] colIndexes, int estimate,
+		int nrUniqueUpperBound) {
 		// exact estimator can ignore upper bound.
 		ABitmap entireBitMap = BitmapEncoder.extractBitmap(colIndexes, _data, _transposed, estimate);
 		EstimationFactors em = estimateCompressedColGroupSize(entireBitMap, colIndexes);
diff --git a/src/main/java/org/apache/sysds/runtime/compress/estim/CompressedSizeEstimatorFactory.java b/src/main/java/org/apache/sysds/runtime/compress/estim/CompressedSizeEstimatorFactory.java
index 6e9208a..a4b1c99 100644
--- a/src/main/java/org/apache/sysds/runtime/compress/estim/CompressedSizeEstimatorFactory.java
+++ b/src/main/java/org/apache/sysds/runtime/compress/estim/CompressedSizeEstimatorFactory.java
@@ -65,7 +65,7 @@ public class CompressedSizeEstimatorFactory {
 		CompressedSizeEstimatorSample estS = new CompressedSizeEstimatorSample(data, cs, sampleSize, k);
 		int double_number = 1;
 		while(estS.getSample() == null) {
-			LOG.error("Warining doubling sample size " + double_number++);
+			LOG.warn("Doubling sample size " + double_number++);
 			sampleSize = sampleSize * 2;
 			if(shouldUseExactEstimator(cs, nRows, sampleSize, nnzRows))
 				return new CompressedSizeEstimatorExact(data, cs);
diff --git a/src/main/java/org/apache/sysds/runtime/compress/estim/CompressedSizeEstimatorSample.java b/src/main/java/org/apache/sysds/runtime/compress/estim/CompressedSizeEstimatorSample.java
index 218e12b..8b9df2c 100644
--- a/src/main/java/org/apache/sysds/runtime/compress/estim/CompressedSizeEstimatorSample.java
+++ b/src/main/java/org/apache/sysds/runtime/compress/estim/CompressedSizeEstimatorSample.java
@@ -94,7 +94,8 @@ public class CompressedSizeEstimatorSample extends CompressedSizeEstimator {
 	}
 
 	@Override
-	public CompressedSizeInfoColGroup estimateCompressedColGroupSize(int[] colIndexes, int estimate, int nrUniqueUpperBound) {
+	public CompressedSizeInfoColGroup estimateCompressedColGroupSize(int[] colIndexes, int estimate,
+		int nrUniqueUpperBound) {
 
 		// extract statistics from sample
 		final ABitmap ubm = BitmapEncoder.extractBitmap(colIndexes, _sample, _transposed, estimate);
@@ -109,7 +110,7 @@ public class CompressedSizeEstimatorSample extends CompressedSizeEstimator {
 	@Override
 	protected CompressedSizeInfoColGroup estimateJoinCompressedSize(int[] joined, CompressedSizeInfoColGroup g1,
 		CompressedSizeInfoColGroup g2, int joinedMaxDistinct) {
-		if((long)g1.getNumVals() * g2.getNumVals() >(long)Integer.MAX_VALUE )
+		if((long) g1.getNumVals() * g2.getNumVals() > (long) Integer.MAX_VALUE)
 			return null;
 
 		final AMapToData map = MapToFactory.join(g1.getMap(), g2.getMap());
diff --git a/src/main/java/org/apache/sysds/runtime/compress/estim/CompressedSizeInfoColGroup.java b/src/main/java/org/apache/sysds/runtime/compress/estim/CompressedSizeInfoColGroup.java
index 1026aa2..5e29272 100644
--- a/src/main/java/org/apache/sysds/runtime/compress/estim/CompressedSizeInfoColGroup.java
+++ b/src/main/java/org/apache/sysds/runtime/compress/estim/CompressedSizeInfoColGroup.java
@@ -183,7 +183,7 @@ public class CompressedSizeInfoColGroup {
 		return _facts.cols;
 	}
 
-	public int getNumRows(){
+	public int getNumRows() {
 		return _facts.numRows;
 	}
 
diff --git a/src/main/java/org/apache/sysds/runtime/compress/estim/EstimationFactors.java b/src/main/java/org/apache/sysds/runtime/compress/estim/EstimationFactors.java
index 28d0821..d6a4005 100644
--- a/src/main/java/org/apache/sysds/runtime/compress/estim/EstimationFactors.java
+++ b/src/main/java/org/apache/sysds/runtime/compress/estim/EstimationFactors.java
@@ -169,7 +169,7 @@ public class EstimationFactors {
 			if(zerosLargestOffset)
 				largestOffs = zerosOffs;
 
-			double overAllSparsity = (double) overallNonZeroCount / ((long)numRows * (long)cols.length);
+			double overAllSparsity = (double) overallNonZeroCount / ((long) numRows * (long) cols.length);
 			double tupleSparsity = (double) tupleNonZeroCount / (numVals * cols.length);
 
 			return new EstimationFactors(cols, numVals, numOffs, largestOffs, frequencies, numRuns, numSingle, numRows,
diff --git a/src/main/java/org/apache/sysds/runtime/compress/lib/CLALibAppend.java b/src/main/java/org/apache/sysds/runtime/compress/lib/CLALibAppend.java
index ab60d9f..daef9ef 100644
--- a/src/main/java/org/apache/sysds/runtime/compress/lib/CLALibAppend.java
+++ b/src/main/java/org/apache/sysds/runtime/compress/lib/CLALibAppend.java
@@ -49,7 +49,7 @@ public class CLALibAppend {
 			left = CompressedMatrixBlockFactory.genUncompressedCompressedMatrixBlock(left);
 		}
 		if(!(right instanceof CompressedMatrixBlock) && m > 1000) {
-			LOG.warn("Appending uncompressed column group right");
+			LOG.info("Appending uncompressed column group right");
 			left = CompressedMatrixBlockFactory.genUncompressedCompressedMatrixBlock(right);
 		}
 
@@ -66,13 +66,12 @@ public class CLALibAppend {
 		ret = appendColGroups(ret, leftC.getColGroups(), rightC.getColGroups(), leftC.getNumColumns());
 
 		double compressedSize = ret.getInMemorySize();
-		double uncompressedSize = MatrixBlock.estimateSizeInMemory(m,n, ret.getSparsity());
+		double uncompressedSize = MatrixBlock.estimateSizeInMemory(m, n, ret.getSparsity());
 
-		
 		if(compressedSize * 10 < uncompressedSize)
 			return ret;
 		else
-			return ret.getUncompressed("Decompressing c bind matrix");
+			return ret.getUncompressed("Decompressing c bind matrix because it had to small compression ratio");
 	}
 
 	private static MatrixBlock appendRightEmpty(CompressedMatrixBlock left, MatrixBlock right) {
diff --git a/src/main/java/org/apache/sysds/runtime/compress/lib/CLALibBinaryCellOp.java b/src/main/java/org/apache/sysds/runtime/compress/lib/CLALibBinaryCellOp.java
index 99d9c92..e330ab8 100644
--- a/src/main/java/org/apache/sysds/runtime/compress/lib/CLALibBinaryCellOp.java
+++ b/src/main/java/org/apache/sysds/runtime/compress/lib/CLALibBinaryCellOp.java
@@ -31,7 +31,9 @@ import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.sysds.runtime.DMLRuntimeException;
 import org.apache.sysds.runtime.compress.CompressedMatrixBlock;
+import org.apache.sysds.runtime.compress.CompressedMatrixBlockFactory;
 import org.apache.sysds.runtime.compress.CompressionSettings;
+import org.apache.sysds.runtime.compress.DMLCompressionException;
 import org.apache.sysds.runtime.compress.colgroup.AColGroup;
 import org.apache.sysds.runtime.compress.colgroup.ColGroupConst;
 import org.apache.sysds.runtime.compress.colgroup.dictionary.ADictionary;
@@ -39,6 +41,7 @@ import org.apache.sysds.runtime.compress.colgroup.dictionary.MatrixBlockDictiona
 import org.apache.sysds.runtime.data.SparseBlock;
 import org.apache.sysds.runtime.functionobjects.Divide;
 import org.apache.sysds.runtime.functionobjects.Minus;
+import org.apache.sysds.runtime.functionobjects.Minus1Multiply;
 import org.apache.sysds.runtime.functionobjects.MinusMultiply;
 import org.apache.sysds.runtime.functionobjects.Multiply;
 import org.apache.sysds.runtime.functionobjects.Plus;
@@ -58,72 +61,107 @@ public class CLALibBinaryCellOp {
 
 	private static final Log LOG = LogFactory.getLog(CLALibBinaryCellOp.class.getName());
 
-	public static MatrixBlock binaryOperations(BinaryOperator op, CompressedMatrixBlock m1, MatrixBlock thatValue,
+	public static MatrixBlock binaryOperations(BinaryOperator op, CompressedMatrixBlock m1, MatrixBlock that,
 		MatrixBlock result) {
-		MatrixBlock that = CompressedMatrixBlock.getUncompressed(thatValue, "Decompressing right side in BinaryOps");
-		if(m1.getNumRows() <= 0)
-			LOG.error(m1);
-		if(that.getNumRows() <= 0)
-			LOG.error(that);
-		LibMatrixBincell.isValidDimensionsBinary(m1, that);
-		BinaryAccessType atype = LibMatrixBincell.getBinaryAccessType(m1, that);
-		return selectProcessingBasedOnAccessType(op, m1, that, result, atype, false);
+		try {
+			if(that.getNumRows() == 1 && that.getNumColumns() == 1) {
+				ScalarOperator sop = new RightScalarOperator(op.fn, that.getValue(0, 0), op.getNumThreads());
+				return CLALibScalar.scalarOperations(sop, m1, result);
+			}
+			if(that.isEmpty())
+				return binaryOperationsEmpty(op, m1, that, result);
+			that = CompressedMatrixBlock.getUncompressed(that, "Decompressing right side in BinaryOps");
+			LibMatrixBincell.isValidDimensionsBinary(m1, that);
+			BinaryAccessType atype = LibMatrixBincell.getBinaryAccessType(m1, that);
+			return selectProcessingBasedOnAccessType(op, m1, that, result, atype, false);
+		}
+		catch(Exception e) {
+			throw new DMLCompressionException("Failed to perform compressed binary operation: " + op, e);
+		}
 	}
 
-	public static MatrixBlock binaryOperationsLeft(BinaryOperator op, CompressedMatrixBlock m1, MatrixBlock thatValue,
+	public static MatrixBlock binaryOperationsLeft(BinaryOperator op, CompressedMatrixBlock m1, MatrixBlock that,
 		MatrixBlock result) {
-		MatrixBlock that = CompressedMatrixBlock.getUncompressed(thatValue, "Decompressing left side in BinaryOps");
+		if(that.getNumRows() == 1 && that.getNumColumns() == 1) {
+			ScalarOperator sop = new LeftScalarOperator(op.fn, that.getValue(0, 0), op.getNumThreads());
+			return CLALibScalar.scalarOperations(sop, m1, result);
+		}
+		if(that.isEmpty())
+			throw new NotImplementedException("Not handling left empty yet");
+
+		that = CompressedMatrixBlock.getUncompressed(that, "Decompressing left side in BinaryOps");
 		LibMatrixBincell.isValidDimensionsBinary(that, m1);
-		thatValue = that;
 		BinaryAccessType atype = LibMatrixBincell.getBinaryAccessType(that, m1);
 		return selectProcessingBasedOnAccessType(op, m1, that, result, atype, true);
 	}
 
+	private static MatrixBlock binaryOperationsEmpty(BinaryOperator op, CompressedMatrixBlock m1, MatrixBlock that,
+		MatrixBlock result) {
+		final ValueFunction fn = op.fn;
+		if((m1.getNumRows() == that.getNumRows() && m1.getNumColumns() == that.getNumColumns()) ||
+			m1.getNumColumns() == that.getNumColumns()) {
+
+			if(fn instanceof Multiply)
+				result = CompressedMatrixBlockFactory.createConstant(m1.getNumRows(), m1.getNumColumns(), 0);
+			else if(fn instanceof Minus1Multiply)
+				result = CompressedMatrixBlockFactory.createConstant(m1.getNumRows(), m1.getNumColumns(), 1);
+			else if(fn instanceof Minus || fn instanceof Plus || fn instanceof MinusMultiply || fn instanceof PlusMultiply){
+				CompressedMatrixBlock ret = new CompressedMatrixBlock();
+				ret.copy(m1);
+				return ret;
+			}
+			else
+				throw new NotImplementedException("Function Type: " + fn);
+
+			return result;
+		}
+		else {
+			final long lr = m1.getNumRows();
+			final long rr = that.getNumRows();
+			final long lc = m1.getNumColumns();
+			final long rc = that.getNumColumns();
+			throw new NotImplementedException(
+				"Not Implemented sizes: left(" + lr + ", " + lc + ") right(" + rr + ", " + rc + ")");
+		}
+	}
+
 	private static MatrixBlock selectProcessingBasedOnAccessType(BinaryOperator op, CompressedMatrixBlock m1,
 		MatrixBlock that, MatrixBlock result, BinaryAccessType atype, boolean left) {
+		final int outRows = m1.getNumRows();
+		final int outCols = m1.getNumColumns();
+		// TODO optimize to allow for sparse outputs.
+		final int outCells = outRows * outCols;
 		if(atype == BinaryAccessType.MATRIX_COL_VECTOR) {
+			result.reset(outRows, Math.max(outCols, that.getNumColumns()), outCells);
 			MatrixBlock d_compressed = m1.getCachedDecompressed();
 			if(d_compressed != null) {
 				if(left)
-					return that.binaryOperations(op, d_compressed, result);
+					LibMatrixBincell.bincellOp(that, d_compressed, result, op);
 				else
-					return d_compressed.binaryOperations(op, that, result);
+					LibMatrixBincell.bincellOp(d_compressed, that, result, op);
+				return result;
 			}
 			else
 				return binaryMVCol(m1, that, op, left);
 
 		}
 		else if(atype == BinaryAccessType.MATRIX_MATRIX) {
-			if(that.isEmpty()) {
-				ScalarOperator sop = left ? new LeftScalarOperator(op.fn, 0, -1) : new RightScalarOperator(op.fn, 0,
-					-1);
-				return CLALibScalar.scalarOperations(sop, m1, result);
-			}
-			else {
-				MatrixBlock d_compressed = m1.getCachedDecompressed();
-				if(d_compressed != null) {
-					// copy the decompressed matrix if there is a decompressed matrix already.
-					MatrixBlock tmp = d_compressed;
-					d_compressed = new MatrixBlock(m1.getNumRows(), m1.getNumColumns(), false);
-					d_compressed.copy(tmp);
-				}
-				else {
-					d_compressed = m1.decompress(op.getNumThreads());
-					m1.clearSoftReferenceToDecompressed();
-				}
+			result.reset(outRows, outCols, outCells);
 
-				if(left)
-					return LibMatrixBincell.bincellOpInPlaceLeft(d_compressed, that, op);
-				else
-					return LibMatrixBincell.bincellOpInPlaceRight(d_compressed, that, op);
-
-			}
+			MatrixBlock d_compressed = m1.getCachedDecompressed();
+			if(d_compressed == null)
+				d_compressed = m1.getUncompressed("MatrixMatrix " + op);
+			
+			if(left)
+				LibMatrixBincell.bincellOp(that, d_compressed, result, op);
+			else
+				LibMatrixBincell.bincellOp(d_compressed, that, result, op);
+			return result;
 		}
 		else if(isSupportedBinaryCellOp(op.fn))
 			return bincellOp(m1, that, setupCompressedReturnMatrixBlock(m1, result), op, left);
 		else {
-			LOG.warn("Decompressing since Binary Ops" + op.fn + " is not supported compressed");
-			return CompressedMatrixBlock.getUncompressed(m1).binaryOperations(op, that, result);
+			return CompressedMatrixBlock.getUncompressed(m1, "BinaryOp: " + op.fn).binaryOperations(op, that, result);
 		}
 	}
 
diff --git a/src/main/java/org/apache/sysds/runtime/compress/lib/CLALibCompAgg.java b/src/main/java/org/apache/sysds/runtime/compress/lib/CLALibCompAgg.java
index 5c9f7b2..62a1c7a 100644
--- a/src/main/java/org/apache/sysds/runtime/compress/lib/CLALibCompAgg.java
+++ b/src/main/java/org/apache/sysds/runtime/compress/lib/CLALibCompAgg.java
@@ -27,8 +27,6 @@ import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Future;
 
 import org.apache.commons.lang.NotImplementedException;
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
 import org.apache.sysds.runtime.DMLRuntimeException;
 import org.apache.sysds.runtime.compress.CompressedMatrixBlock;
 import org.apache.sysds.runtime.compress.CompressionSettings;
@@ -58,10 +56,7 @@ import org.apache.sysds.runtime.matrix.operators.BinaryOperator;
 import org.apache.sysds.runtime.util.CommonThreadPool;
 
 public class CLALibCompAgg {
-
-	private static final Log LOG = LogFactory.getLog(CLALibCompAgg.class.getName());
-
-	// private static final long MIN_PAR_AGG_THRESHOLD = 8 * 1024 * 1024;
+	// private static final Log LOG = LogFactory.getLog(CLALibCompAgg.class.getName());
 	private static final long MIN_PAR_AGG_THRESHOLD = 8 * 1024;
 
 	private static ThreadLocal<MatrixBlock> memPool = new ThreadLocal<MatrixBlock>() {
@@ -87,14 +82,13 @@ public class CLALibCompAgg {
 
 			if(denseSize < 5 * currentSize && inputMatrix.getColGroups().size() > 5 &&
 				denseSize <= localMaxMemory / 2) {
-				LOG.info("Decompressing for unaryAggregate because of overlapping state");
-				inputMatrix.decompress(op.getNumThreads());
+				inputMatrix.getUncompressed("Decompressing for unaryAggregate because of overlapping state");
 			}
 			MatrixBlock decomp = inputMatrix.getCachedDecompressed();
 			if(decomp != null)
 				return decomp.aggregateUnaryOperations(op, result, blen, indexesIn, inCP);
 		}
-		
+
 		// initialize and allocate the result
 		if(result == null)
 			result = new MatrixBlock(tempCellIndex.row, tempCellIndex.column, false);
@@ -113,7 +107,7 @@ public class CLALibCompAgg {
 			else
 				aggregateUnaryNormalCompressedMatrixBlock(inputMatrix, result, opm, blen, indexesIn, inCP);
 		}
-		
+
 		result.recomputeNonZeros();
 		if(op.aggOp.existsCorrection() && !inCP) {
 			result = addCorrection(result, op);
@@ -256,8 +250,7 @@ public class CLALibCompAgg {
 					f.get();
 		}
 		catch(InterruptedException | ExecutionException e) {
-			LOG.error("Aggregate In parallel failed.");
-			throw new DMLRuntimeException(e);
+			throw new DMLRuntimeException("Aggregate In parallel failed.", e);
 		}
 	}
 
diff --git a/src/main/java/org/apache/sysds/runtime/compress/lib/CLALibLeftMultBy.java b/src/main/java/org/apache/sysds/runtime/compress/lib/CLALibLeftMultBy.java
index 5fc9016..8b78e58 100644
--- a/src/main/java/org/apache/sysds/runtime/compress/lib/CLALibLeftMultBy.java
+++ b/src/main/java/org/apache/sysds/runtime/compress/lib/CLALibLeftMultBy.java
@@ -58,11 +58,11 @@ public class CLALibLeftMultBy {
 		return ret;
 	}
 
-	public static MatrixBlock leftMultByMatrixTransposed(CompressedMatrixBlock m1, CompressedMatrixBlock m2,
+	public static MatrixBlock leftMultByMatrixTransposed(CompressedMatrixBlock right, CompressedMatrixBlock left,
 		MatrixBlock ret, int k) {
-
-		ret = prepareReturnMatrix(m1, m2, ret, true);
-		leftMultByCompressedTransposedMatrix(m1.getColGroups(), m2, ret, k, m1.getNumColumns(), m1.isOverlapping());
+		LOG.warn("Compressed Compressed matrix multiplication");
+		ret = prepareReturnMatrix(right, left, ret, true);
+		leftMultByCompressedTransposedMatrix(right, left, ret, k);
 
 		ret.recomputeNonZeros();
 		return ret;
@@ -79,6 +79,15 @@ public class CLALibLeftMultBy {
 		return ret;
 	}
 
+	/**
+	 * Prepare the output matrix.
+	 * 
+	 * @param m1          The right hand side matrix
+	 * @param m2          The left hand side matrix
+	 * @param ret         The output matrix to reallocate
+	 * @param doTranspose Boolean specifying if the m2 (left side) matrix should be considered transposed
+	 * @return the result matrix allocated.
+	 */
 	private static MatrixBlock prepareReturnMatrix(MatrixBlock m1, MatrixBlock m2, MatrixBlock ret,
 		boolean doTranspose) {
 		final int numRowsOutput = doTranspose ? m2.getNumColumns() : m2.getNumRows();
@@ -87,6 +96,8 @@ public class CLALibLeftMultBy {
 			ret = new MatrixBlock(numRowsOutput, numColumnsOutput, false, numRowsOutput * numColumnsOutput);
 		else if(!(ret.getNumColumns() == numColumnsOutput && ret.getNumRows() == numRowsOutput && ret.isAllocated()))
 			ret.reset(numRowsOutput, numColumnsOutput, false, numRowsOutput * numColumnsOutput);
+
+		ret.allocateDenseBlock();
 		return ret;
 	}
 
@@ -94,11 +105,9 @@ public class CLALibLeftMultBy {
 		final boolean overlapping = cmb.isOverlapping();
 		final List<AColGroup> groups = cmb.getColGroups();
 
-		result.allocateDenseBlock();
-
 		if(overlapping) {
 			LOG.warn("Inefficient TSMM with overlapping matrix could be implemented multi-threaded but is not yet.");
-			leftMultByCompressedTransposedMatrix(groups, groups, result);
+			multAllColGroups(groups, groups, result);
 		}
 		else {
 			final boolean containsSDC = containsSDC(groups);
@@ -153,26 +162,29 @@ public class CLALibLeftMultBy {
 
 	}
 
-	private static MatrixBlock leftMultByCompressedTransposedMatrix(List<AColGroup> colGroups,
-		CompressedMatrixBlock that, MatrixBlock ret, int k, int numColumns, boolean overlapping) {
+	private static MatrixBlock leftMultByCompressedTransposedMatrix(CompressedMatrixBlock right,
+		CompressedMatrixBlock left, MatrixBlock ret, int k) {
 
-		ret.allocateDenseBlock();
-		List<AColGroup> thatCGs = that.getColGroups();
+		final List<AColGroup> thisCGs = right.getColGroups();
+		final List<AColGroup> thatCGs = left.getColGroups();
+
+		final boolean thisOverlapping = right.isOverlapping();
+		final boolean thatOverlapping = left.isOverlapping();
+		final boolean anyOverlap = thisOverlapping || thatOverlapping;
 
-		if(k <= 1 || overlapping || that.isOverlapping()) {
-			if(overlapping || that.isOverlapping())
+		if(k <= 1 || anyOverlap) {
+			if(anyOverlap)
 				LOG.warn("Inefficient Compressed multiplication with overlapping matrix"
 					+ " could be implemented multi-threaded but is not yet.");
-			leftMultByCompressedTransposedMatrix(colGroups, thatCGs, ret);
+			multAllColGroups(thisCGs, thatCGs, ret);
 		}
 		else {
-
 			try {
 				ExecutorService pool = CommonThreadPool.get(k);
 				ArrayList<Callable<Object>> tasks = new ArrayList<>();
-				for(int i = 0; i < thatCGs.size(); i++) {
-					tasks.add(new LeftMultByCompressedTransposedMatrixTask(colGroups, thatCGs.get(i), ret));
-				}
+				for(int i = 0; i < thatCGs.size(); i++)
+					for(int j = 0; j < thisCGs.size(); j++)
+						tasks.add(new LeftMultByCompressedTransposedMatrixTask(thisCGs.get(j), thatCGs.get(i), ret));
 
 				for(Future<Object> tret : pool.invokeAll(tasks))
 					tret.get();
@@ -182,29 +194,29 @@ public class CLALibLeftMultBy {
 				throw new DMLRuntimeException(e);
 			}
 		}
+
 		ret.recomputeNonZeros();
 		return ret;
 	}
 
 	private static class LeftMultByCompressedTransposedMatrixTask implements Callable<Object> {
-		private final List<AColGroup> _groups;
+		private final AColGroup _right;
 		private final AColGroup _left;
 		private final MatrixBlock _ret;
-		private final int _start;
-		private final int _end;
 
-		protected LeftMultByCompressedTransposedMatrixTask(List<AColGroup> groups, AColGroup left, MatrixBlock ret) {
-			_groups = groups;
+		protected LeftMultByCompressedTransposedMatrixTask(AColGroup right, AColGroup left, MatrixBlock ret) {
+			_right = right;
 			_left = left;
 			_ret = ret;
-			_start = 0;
-			_end = groups.size();
 		}
 
 		@Override
 		public Object call() {
 			try {
-				leftMultByCompressedTransposedMatrix(_left, _groups, _ret, _start, _end);
+				if(_right != _left)
+					_right.leftMultByAColGroup(_left, _ret);
+				else
+					_right.tsmm(_ret);
 			}
 			catch(Exception e) {
 				e.printStackTrace();
@@ -214,21 +226,16 @@ public class CLALibLeftMultBy {
 		}
 	}
 
-	private static void leftMultByCompressedTransposedMatrix(List<AColGroup> thisCG, List<AColGroup> thatCG,
-		MatrixBlock ret) {
-		for(AColGroup lhs : thatCG)
-			leftMultByCompressedTransposedMatrix(lhs, thisCG, ret, 0, thisCG.size());
-	}
-
-	private static void leftMultByCompressedTransposedMatrix(AColGroup lhs, List<AColGroup> thisCG, MatrixBlock ret,
-		int colGroupStart, int colGroupEnd) {
-
-		for(; colGroupStart < colGroupEnd; colGroupStart++) {
-			AColGroup rhs = thisCG.get(colGroupStart);
-			if(rhs != lhs)
-				rhs.leftMultByAColGroup(lhs, ret);
-			else
-				rhs.tsmm(ret);
+	private static void multAllColGroups(List<AColGroup> right, List<AColGroup> left, MatrixBlock ret) {
+		for(int i = 0; i < left.size(); i++) {
+			AColGroup leftCG = left.get(i);
+			for(int j = 0; j < right.size(); j++) {
+				AColGroup rightCG = right.get(j);
+				if(rightCG != leftCG)
+					rightCG.leftMultByAColGroup(leftCG, ret);
+				else
+					rightCG.tsmm(ret);
+			}
 		}
 	}
 
@@ -244,14 +251,12 @@ public class CLALibLeftMultBy {
 		try {
 			ExecutorService pool = CommonThreadPool.get(k);
 			ArrayList<Callable<Object>> tasks = new ArrayList<>();
-			// if(groups.size()< 10){
 
-			// }
 			final int numColGroups = groups.size();
 			for(int i = 0; i < numColGroups; i++) {
 				tasks.add(new tsmmSelfColGroupTask(groups.get(i), ret));
-				for(int j = i +1; j < numColGroups; j++)
-					tasks.add(new tsmmColGroupTask(groups, filteredGroups, ret, i, j, j+1));
+				for(int j = i + 1; j < numColGroups; j++)
+					tasks.add(new tsmmColGroupTask(groups, filteredGroups, ret, i, j, j + 1));
 			}
 
 			for(Future<Object> tret : pool.invokeAll(tasks))
@@ -273,7 +278,7 @@ public class CLALibLeftMultBy {
 		final AColGroup full_lhs = groups.get(i);
 		final AColGroup lhs = filteredGroups.get(i);
 		boolean isSDC = full_lhs instanceof ColGroupSDC || full_lhs instanceof ColGroupSDCSingle;
-		for(int id = start ; id < end; id++) {
+		for(int id = start; id < end; id++) {
 			final AColGroup full_rhs = groups.get(id);
 			final AColGroup rhs = filteredGroups.get(id);
 			if(isSDC && (full_rhs instanceof ColGroupSDC || full_rhs instanceof ColGroupSDCSingle))
@@ -299,7 +304,6 @@ public class CLALibLeftMultBy {
 		final double[] constV = containsSDC ? new double[numColumnsOut] : null;
 		final List<AColGroup> filteredGroups = filterSDCGroups(colGroups, constV);
 
-		ret.allocateDenseBlock();
 		final double[] rowSums = containsSDC ? new double[that.getNumRows()] : null;
 
 		if(k == 1) {
@@ -329,7 +333,6 @@ public class CLALibLeftMultBy {
 				}
 				else {
 					final int numberSplits = Math.max((k / (ret.getNumRows() / rowBlockSize)), 1);
-					// LOG.error("RowBLockSize:" +rowBlockSize + " Splits " + numberSplits);
 					if(numberSplits == 1) {
 						for(int blo = 0; blo < that.getNumRows(); blo += rowBlockSize) {
 							tasks.add(new LeftMatrixColGroupMultTaskNew(filteredGroups, that, ret, blo,
@@ -465,7 +468,8 @@ public class CLALibLeftMultBy {
 		private final int _start;
 		private final int _end;
 
-		protected tsmmColGroupTask(List<AColGroup> groups, List<AColGroup> filteredGroups, MatrixBlock ret, int i, int start, int end) {
+		protected tsmmColGroupTask(List<AColGroup> groups, List<AColGroup> filteredGroups, MatrixBlock ret, int i,
+			int start, int end) {
 			_groups = groups;
 			_filteredGroups = filteredGroups;
 			_ret = ret;
diff --git a/src/main/java/org/apache/sysds/runtime/compress/lib/CLALibRightMultBy.java b/src/main/java/org/apache/sysds/runtime/compress/lib/CLALibRightMultBy.java
index edc68b5..fb4be0d 100644
--- a/src/main/java/org/apache/sysds/runtime/compress/lib/CLALibRightMultBy.java
+++ b/src/main/java/org/apache/sysds/runtime/compress/lib/CLALibRightMultBy.java
@@ -28,8 +28,6 @@ import java.util.concurrent.ExecutionException;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Future;
 
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
 import org.apache.sysds.runtime.DMLRuntimeException;
 import org.apache.sysds.runtime.compress.CompressedMatrixBlock;
 import org.apache.sysds.runtime.compress.colgroup.AColGroup;
@@ -38,68 +36,52 @@ import org.apache.sysds.runtime.matrix.data.MatrixBlock;
 import org.apache.sysds.runtime.util.CommonThreadPool;
 
 public class CLALibRightMultBy {
-	private static final Log LOG = LogFactory.getLog(CLALibRightMultBy.class.getName());
+	// private static final Log LOG = LogFactory.getLog(CLALibRightMultBy.class.getName());
 
 	public static MatrixBlock rightMultByMatrix(CompressedMatrixBlock m1, MatrixBlock m2, MatrixBlock ret, int k,
 		boolean allowOverlap) {
-		ret = rightMultByMatrix(m1.getColGroups(), m2, ret, k, allowOverlap);
-		ret.recomputeNonZeros();
-		return ret;
-	}
-
-	private static MatrixBlock rightMultByMatrix(List<AColGroup> colGroups, MatrixBlock that, MatrixBlock ret, int k,
-		boolean allowOverlap) {
-
-		if(that instanceof CompressedMatrixBlock)
-			LOG.warn("Decompression Right matrix");
-
-		that = that instanceof CompressedMatrixBlock ? ((CompressedMatrixBlock) that).decompress(k) : that;
-
-		MatrixBlock m = rightMultByMatrixOverlapping(colGroups, that, ret, k);
-
-		if(m instanceof CompressedMatrixBlock)
-			if(allowOverlappingOutput(colGroups, allowOverlap))
-				return m;
+		if(m2.isEmpty()) {
+			if(ret == null)
+				ret = new MatrixBlock(m1.getNumRows(), m2.getNumColumns(), 0);
 			else
-				return ((CompressedMatrixBlock) m).decompress(k);
-		else
-			return m;
-	}
+				ret.reset(m1.getNumRows(), m2.getNumColumns(), 0);
+		}
+		else {
+			if(m2 instanceof CompressedMatrixBlock) {
+				CompressedMatrixBlock m2C = (CompressedMatrixBlock) m2;
+				m2 = m2C.getUncompressed("Uncompressed right side of right MM");
+			}
 
-	private static boolean allowOverlappingOutput(List<AColGroup> colGroups, boolean allowOverlap) {
+			ret = rightMultByMatrixOverlapping(m1, m2, ret, k);
 
-		if(!allowOverlap) {
-			LOG.debug("Not Overlapping because it is not allowed");
-			return false;
+			if(ret instanceof CompressedMatrixBlock) {
+				if(!allowOverlap) {
+					ret = ((CompressedMatrixBlock) ret).getUncompressed("Overlapping not allowed");
+				}
+				else {
+					final double compressedSize = ret.getInMemorySize();
+					final double uncompressedSize = MatrixBlock.estimateSizeDenseInMemory(ret.getNumRows(),
+						ret.getNumColumns());
+					if(compressedSize * 2 > uncompressedSize)
+						ret = ((CompressedMatrixBlock) ret).getUncompressed(
+							"Overlapping rep to big: " + compressedSize + " vs Uncompressed " + uncompressedSize);
+				}
+			}
 		}
-		else
-			return true;
-		// int distinctCount = 0;
-		// for(AColGroup g : colGroups) {
-		// if(g instanceof ColGroupCompressed)
-		// distinctCount += ((ColGroupCompressed) g).getNumValues();
-		// else {
-		// LOG.debug("Not Overlapping because there is an un-compressed column group");
-		// return false;
-		// }
-		// }
-		// final int threshold = colGroups.get(0).getNumRows() / 2;
-		// boolean allow = distinctCount <= threshold;
-		// if(LOG.isDebugEnabled() && !allow)
-		// LOG.debug("Not Allowing Overlap because of number of distinct items in compression: " + distinctCount
-		// + " is greater than threshold: " + threshold);
-		// return allow;
 
+		ret.recomputeNonZeros();
+
+		return ret;
 	}
 
-	private static MatrixBlock rightMultByMatrixOverlapping(List<AColGroup> colGroups, MatrixBlock that,
-		MatrixBlock ret, int k) {
-		int rl = colGroups.get(0).getNumRows();
+	private static MatrixBlock rightMultByMatrixOverlapping(CompressedMatrixBlock m1, MatrixBlock that, MatrixBlock ret,
+		int k) {
+		int rl = m1.getNumRows();
 		int cl = that.getNumColumns();
 		// Create an overlapping compressed Matrix Block.
 		ret = new CompressedMatrixBlock(rl, cl);
 		CompressedMatrixBlock retC = (CompressedMatrixBlock) ret;
-		ret = rightMultByMatrixCompressed(colGroups, that, retC, k);
+		ret = rightMultByMatrixCompressed(m1.getColGroups(), that, retC, k);
 		return ret;
 	}
 
diff --git a/src/main/java/org/apache/sysds/runtime/compress/readers/ReaderCompressedSelection.java b/src/main/java/org/apache/sysds/runtime/compress/readers/ReaderCompressedSelection.java
index 47941ab..5e347af 100644
--- a/src/main/java/org/apache/sysds/runtime/compress/readers/ReaderCompressedSelection.java
+++ b/src/main/java/org/apache/sysds/runtime/compress/readers/ReaderCompressedSelection.java
@@ -63,9 +63,7 @@ public class ReaderCompressedSelection extends ReaderColumnSelection {
 			reusableArr[i] = bl.get(offset, _colIndexes[i]);
 			bl.set(offset, _colIndexes[i], 0);
 		}
-		// LOG.error(reusableReturn);
 		return reusableReturn;
-
 	}
 
 }
diff --git a/src/main/java/org/apache/sysds/runtime/compress/workload/AWTreeNode.java b/src/main/java/org/apache/sysds/runtime/compress/workload/AWTreeNode.java
index ce965c8..4941def 100644
--- a/src/main/java/org/apache/sysds/runtime/compress/workload/AWTreeNode.java
+++ b/src/main/java/org/apache/sysds/runtime/compress/workload/AWTreeNode.java
@@ -46,8 +46,8 @@ public abstract class AWTreeNode {
 	}
 
 	private final WTNodeType _type;
-	private final List<WTreeNode> _children = new ArrayList<>();
-	private final List<Op> _ops = new ArrayList<>();
+	protected final List<WTreeNode> _children = new ArrayList<>();
+	protected final List<Op> _ops = new ArrayList<>();
 
 	public AWTreeNode(WTNodeType type) {
 		_type = type;
@@ -102,7 +102,7 @@ public abstract class AWTreeNode {
 	public String toString() {
 		StringBuilder sb = new StringBuilder();
 		sb.append("\n---------------------------Workload Tree:---------------------------------------\n");
-		sb.append(this.explain(1));
+		sb.append(this.explain(0));
 		sb.append("--------------------------------------------------------------------------------\n");
 		return sb.toString();
 	}
diff --git a/src/main/java/org/apache/sysds/runtime/compress/workload/Op.java b/src/main/java/org/apache/sysds/runtime/compress/workload/Op.java
index 32b4b34..1825a02 100644
--- a/src/main/java/org/apache/sysds/runtime/compress/workload/Op.java
+++ b/src/main/java/org/apache/sysds/runtime/compress/workload/Op.java
@@ -24,6 +24,9 @@ import org.apache.sysds.hops.Hop;
 public abstract class Op {
 
 	protected final Hop _op;
+	protected boolean isDecompressing = false;
+	protected boolean isOverlapping = false;
+	private boolean isDensifying = false;
 
 	public Op(Hop op) {
 		_op = op;
@@ -35,11 +38,35 @@ public abstract class Op {
 
 	@Override
 	public String toString() {
-		return _op.toString();
+		return _op.getHopID() + " " + _op.toString() + " CompressedOutput: " + isCompressedOutput()
+			+ " IsDecompressing: " + isDecompressing();
 	}
 
-	public abstract boolean isCompressedOutput();
+	public boolean isCompressedOutput(){
+		return true;
+	}
+
+	public final boolean isDecompressing() {
+		return isDecompressing;
+	}
 
-	public abstract boolean isDecompressing();
+	public final void setDecompressing() {
+		isDecompressing = true;
+	}
+
+	public boolean isOverlapping() {
+		return isOverlapping;
+	}
 
+	public void setOverlapping() {
+		isOverlapping = true;
+	}
+
+	public boolean isDensifying(){
+		return isDensifying;
+	}
+
+	public void setDensifying(){
+		isDensifying = true;
+	}
 }
diff --git a/src/main/java/org/apache/sysds/runtime/compress/workload/OpDecompressing.java b/src/main/java/org/apache/sysds/runtime/compress/workload/OpDecompressing.java
deleted file mode 100644
index 8141b3c..0000000
--- a/src/main/java/org/apache/sysds/runtime/compress/workload/OpDecompressing.java
+++ /dev/null
@@ -1,39 +0,0 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License.  You may obtain a copy of the License at
- *
- *   http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-package org.apache.sysds.runtime.compress.workload;
-
-import org.apache.sysds.hops.Hop;
-
-public class OpDecompressing extends Op {
-
-	public OpDecompressing(Hop op) {
-		super(op);
-	}
-
-	@Override
-	public boolean isCompressedOutput() {
-		return false;
-	}
-
-	@Override
-	public boolean isDecompressing(){
-		return true;
-	}
-}
diff --git a/src/main/java/org/apache/sysds/runtime/compress/workload/OpMetadata.java b/src/main/java/org/apache/sysds/runtime/compress/workload/OpMetadata.java
index 1792eb6..386e9c4 100644
--- a/src/main/java/org/apache/sysds/runtime/compress/workload/OpMetadata.java
+++ b/src/main/java/org/apache/sysds/runtime/compress/workload/OpMetadata.java
@@ -23,17 +23,14 @@ import org.apache.sysds.hops.Hop;
 
 public class OpMetadata extends Op {
 
-	public OpMetadata(Hop op) {
-		super(op);
-	}
+	final Hop parent;
 
-	@Override
-	public boolean isCompressedOutput() {
-		return true;
+	public OpMetadata(Hop op, Hop parent) {
+		super(op);
+		this.parent = parent;
 	}
 
-	@Override
-	public boolean isDecompressing() {
-		return false;
+	public Hop getParent(){
+		return parent;
 	}
 }
diff --git a/src/main/java/org/apache/sysds/runtime/compress/workload/OpNormal.java b/src/main/java/org/apache/sysds/runtime/compress/workload/OpNormal.java
index 0c1abdc..e13848f 100644
--- a/src/main/java/org/apache/sysds/runtime/compress/workload/OpNormal.java
+++ b/src/main/java/org/apache/sysds/runtime/compress/workload/OpNormal.java
@@ -34,9 +34,4 @@ public class OpNormal extends Op {
 	public boolean isCompressedOutput() {
 		return outC;
 	}
-
-	@Override
-	public boolean isDecompressing() {
-		return false;
-	}
 }
diff --git a/src/main/java/org/apache/sysds/runtime/compress/workload/OpOverlappingDecompress.java b/src/main/java/org/apache/sysds/runtime/compress/workload/OpOverlappingDecompress.java
deleted file mode 100644
index 76307c4..0000000
--- a/src/main/java/org/apache/sysds/runtime/compress/workload/OpOverlappingDecompress.java
+++ /dev/null
@@ -1,38 +0,0 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License.  You may obtain a copy of the License at
- *
- *   http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-package org.apache.sysds.runtime.compress.workload;
-
-import org.apache.sysds.hops.Hop;
-
-public class OpOverlappingDecompress extends Op {
-	public OpOverlappingDecompress(Hop op) {
-		super(op);
-	}
-
-	@Override
-	public boolean isCompressedOutput() {
-		return false;
-	}
-
-	@Override
-	public boolean isDecompressing() {
-		return true;
-	}
-}
diff --git a/src/main/java/org/apache/sysds/runtime/compress/workload/OpSided.java b/src/main/java/org/apache/sysds/runtime/compress/workload/OpSided.java
index 4b8549e..d13912e 100644
--- a/src/main/java/org/apache/sysds/runtime/compress/workload/OpSided.java
+++ b/src/main/java/org/apache/sysds/runtime/compress/workload/OpSided.java
@@ -30,15 +30,12 @@ public class OpSided extends Op {
 	private final boolean _tLeft;
 	private final boolean _tRight;
 
-	private boolean _overlappingDecompression = false;
-
 	public OpSided(Hop op, boolean cLeft, boolean cRight, boolean tLeft, boolean tRight) {
 		super(op);
 		_cLeft = cLeft;
 		_cRight = cRight;
 		_tLeft = tLeft;
 		_tRight = tRight;
-
 	}
 
 	public boolean getLeft() {
@@ -60,7 +57,6 @@ public class OpSided extends Op {
 	@Override
 	public String toString() {
 		return super.toString() + " L:" + _cLeft + " R:" + _cRight + " tL:" + _tLeft + " tR:" + _tRight + " ";
-
 	}
 
 	public boolean isLeftMM() {
@@ -77,15 +73,8 @@ public class OpSided extends Op {
 
 	@Override
 	public boolean isCompressedOutput() {
-		return isRightMM() && !_overlappingDecompression;
+		// if the output is transposed after a right matrix multiplication the compression is decompressed
+		return _cLeft && !_cRight && !_tLeft;
 	}
 
-	protected void setOverlappingDecompression(boolean v) {
-		_overlappingDecompression = v;
-	}
-
-	@Override
-	public boolean isDecompressing() {
-		return _overlappingDecompression;
-	}
 }
diff --git a/src/main/java/org/apache/sysds/runtime/compress/workload/WTreeRoot.java b/src/main/java/org/apache/sysds/runtime/compress/workload/WTreeRoot.java
index b08ec64..c3b3818 100644
--- a/src/main/java/org/apache/sysds/runtime/compress/workload/WTreeRoot.java
+++ b/src/main/java/org/apache/sysds/runtime/compress/workload/WTreeRoot.java
@@ -19,8 +19,6 @@
 
 package org.apache.sysds.runtime.compress.workload;
 
-import java.util.List;
-
 import org.apache.sysds.hops.Hop;
 
 /**
@@ -32,12 +30,11 @@ public class WTreeRoot extends AWTreeNode {
 
 	private final Hop _root;
 
-	private final List<Hop> _decompressList;
+	private boolean isDecompressing = false;
 
-	public WTreeRoot(Hop root, List<Hop> decompressList) {
+	public WTreeRoot(Hop root) {
 		super(WTNodeType.ROOT);
 		_root = root;
-		_decompressList = decompressList;
 	}
 
 	/**
@@ -49,7 +46,27 @@ public class WTreeRoot extends AWTreeNode {
 		return _root;
 	}
 
-	public List<Hop> getDecompressList() {
-		return _decompressList;
+	public boolean isDecompressing() {
+		return isDecompressing;
+	}
+
+	public void setDecompressing() {
+		isDecompressing = true;
 	}
+
+	@Override
+	protected String explain(int level) {
+		StringBuilder sb = new StringBuilder();
+	
+		// append node summary
+		sb.append("ROOT : " + _root.toString());
+		sb.append("\n");
+
+		// append child nodes
+		if(!_children.isEmpty())
+			for(AWTreeNode n : _children)
+				sb.append(n.explain(level + 1));
+		return sb.toString();
+	}
+
 }
diff --git a/src/main/java/org/apache/sysds/runtime/compress/workload/WorkloadAnalyzer.java b/src/main/java/org/apache/sysds/runtime/compress/workload/WorkloadAnalyzer.java
index c865507..e086974 100644
--- a/src/main/java/org/apache/sysds/runtime/compress/workload/WorkloadAnalyzer.java
+++ b/src/main/java/org/apache/sysds/runtime/compress/workload/WorkloadAnalyzer.java
@@ -30,20 +30,25 @@ import java.util.Set;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
+import org.apache.sysds.common.Types.AggOp;
 import org.apache.sysds.common.Types.OpOp1;
 import org.apache.sysds.common.Types.OpOp2;
+import org.apache.sysds.common.Types.OpOp3;
 import org.apache.sysds.common.Types.OpOpData;
 import org.apache.sysds.common.Types.ReOrgOp;
 import org.apache.sysds.hops.AggBinaryOp;
+import org.apache.sysds.hops.AggUnaryOp;
+import org.apache.sysds.hops.BinaryOp;
 import org.apache.sysds.hops.FunctionOp;
 import org.apache.sysds.hops.Hop;
 import org.apache.sysds.hops.IndexingOp;
 import org.apache.sysds.hops.LiteralOp;
+import org.apache.sysds.hops.ParameterizedBuiltinOp;
 import org.apache.sysds.hops.ReorgOp;
+import org.apache.sysds.hops.UnaryOp;
 import org.apache.sysds.hops.rewrite.HopRewriteUtils;
 import org.apache.sysds.hops.rewrite.RewriteCompressedReblock;
 import org.apache.sysds.parser.DMLProgram;
-import org.apache.sysds.parser.DataIdentifier;
 import org.apache.sysds.parser.ForStatement;
 import org.apache.sysds.parser.ForStatementBlock;
 import org.apache.sysds.parser.FunctionStatement;
@@ -54,8 +59,9 @@ import org.apache.sysds.parser.ParForStatementBlock;
 import org.apache.sysds.parser.StatementBlock;
 import org.apache.sysds.parser.WhileStatement;
 import org.apache.sysds.parser.WhileStatementBlock;
-import org.apache.sysds.runtime.compress.cost.CostEstimatorBuilder;
+import org.apache.sysds.runtime.compress.DMLCompressionException;
 import org.apache.sysds.runtime.compress.workload.AWTreeNode.WTNodeType;
+import org.apache.sysds.utils.Explain;
 
 public class WorkloadAnalyzer {
 	private static final Log LOG = LogFactory.getLog(WorkloadAnalyzer.class.getName());
@@ -64,30 +70,29 @@ public class WorkloadAnalyzer {
 	// avoid wtree construction for assumptionly already compressed intermediates
 	// (due to conditional control flow this might miss compression opportunities)
 	public static boolean PRUNE_COMPRESSED_INTERMEDIATES = true;
-	
+
 	private final Set<Hop> visited;
 	private final Set<Long> compressed;
 	private final Set<Long> transposed;
-	private final Set<String> transientCompressed;
+	private final Map<String, Long> transientCompressed;
 	private final Set<Long> overlapping;
-	private final Set<String> transientOverlapping;
 	private final DMLProgram prog;
-	private final List<Hop> decompressHops;
+	private final Map<Long, Op> treeLookup;
 
 	public static Map<Long, WTreeRoot> getAllCandidateWorkloads(DMLProgram prog) {
 		// extract all compression candidates from program (in program order)
 		List<Hop> candidates = getCandidates(prog);
-		
+
 		// for each candidate, create pruned workload tree
 		List<WorkloadAnalyzer> allWAs = new LinkedList<>();
 		Map<Long, WTreeRoot> map = new HashMap<>();
 		for(Hop cand : candidates) {
-			//prune already covered candidate (intermediate already compressed)
-			if( PRUNE_COMPRESSED_INTERMEDIATES )
-				if( allWAs.stream().anyMatch(w -> w.containsCompressed(cand)) )
-					continue; //intermediate already compressed
-			
-			//construct workload tree for candidate
+			// prune already covered candidate (intermediate already compressed)
+			if(PRUNE_COMPRESSED_INTERMEDIATES)
+				if(allWAs.stream().anyMatch(w -> w.containsCompressed(cand)))
+					continue; // intermediate already compressed
+
+			// construct workload tree for candidate
 			WorkloadAnalyzer wa = new WorkloadAnalyzer(prog);
 			WTreeRoot tree = wa.createWorkloadTree(cand);
 			map.put(cand.getHopID(), tree);
@@ -102,10 +107,9 @@ public class WorkloadAnalyzer {
 		this.visited = new HashSet<>();
 		this.compressed = new HashSet<>();
 		this.transposed = new HashSet<>();
-		this.transientCompressed = new HashSet<>();
+		this.transientCompressed = new HashMap<>();
 		this.overlapping = new HashSet<>();
-		this.transientOverlapping = new HashSet<>();
-		this.decompressHops = new ArrayList<>();
+		this.treeLookup = new HashMap<>();
 	}
 
 	protected WorkloadAnalyzer(DMLProgram prog, Set<Long> overlapping) {
@@ -113,28 +117,25 @@ public class WorkloadAnalyzer {
 		this.visited = new HashSet<>();
 		this.compressed = new HashSet<>();
 		this.transposed = new HashSet<>();
-		this.transientCompressed = new HashSet<>();
+		this.transientCompressed = new HashMap<>();
 		this.overlapping = overlapping;
-		this.transientOverlapping = new HashSet<>();
-		this.decompressHops = new ArrayList<>();
+		this.treeLookup = new HashMap<>();
 	}
 
-	protected WorkloadAnalyzer(DMLProgram prog, Set<Long> compressed, Set<String> transientCompressed,
-		Set<Long> transposed, Set<Long> overlapping, Set<String> transientOverlapping) {
+	protected WorkloadAnalyzer(DMLProgram prog, Set<Long> compressed, HashMap<String, Long> transientCompressed,
+		Set<Long> transposed, Set<Long> overlapping, Map<Long, Op> treeLookup) {
 		this.prog = prog;
 		this.visited = new HashSet<>();
 		this.compressed = compressed;
 		this.transposed = transposed;
 		this.transientCompressed = transientCompressed;
 		this.overlapping = overlapping;
-		this.transientOverlapping = transientOverlapping;
-		this.decompressHops = new ArrayList<>();
+		this.treeLookup = treeLookup;
 	}
 
 	protected WTreeRoot createWorkloadTree(Hop candidate) {
-		WTreeRoot main = new WTreeRoot(candidate, decompressHops);
+		WTreeRoot main = new WTreeRoot(candidate);
 		compressed.add(candidate.getHopID());
-		transientCompressed.add(candidate.getName());
 		for(StatementBlock sb : prog.getStatementBlocks())
 			createWorkloadTree(main, sb, prog, new HashSet<>());
 		pruneWorkloadTree(main);
@@ -144,7 +145,7 @@ public class WorkloadAnalyzer {
 	protected boolean containsCompressed(Hop hop) {
 		return compressed.contains(hop.getHopID());
 	}
-	
+
 	private static List<Hop> getCandidates(DMLProgram prog) {
 		List<Hop> candidates = new ArrayList<>();
 		for(StatementBlock sb : prog.getStatementBlocks()) {
@@ -208,9 +209,8 @@ public class WorkloadAnalyzer {
 		if(hop.isVisited())
 			return;
 		// evaluate and add candidates (type and size)
-		if( (  RewriteCompressedReblock.satisfiesAggressiveCompressionCondition(hop)
-				& ALLOW_INTERMEDIATE_CANDIDATES)
-			|| RewriteCompressedReblock.satisfiesCompressionCondition(hop))
+		if((RewriteCompressedReblock.satisfiesAggressiveCompressionCondition(hop) & ALLOW_INTERMEDIATE_CANDIDATES) ||
+			RewriteCompressedReblock.satisfiesCompressionCondition(hop))
 			cands.add(hop);
 
 		// recursively process children (inputs)
@@ -287,23 +287,27 @@ public class WorkloadAnalyzer {
 							FunctionStatementBlock fsb = prog.getFunctionStatementBlock(fop.getFunctionKey());
 							if(fsb == null)
 								continue;
-							FunctionStatement fstmt = (FunctionStatement) fsb.getStatement(0);
-							Set<String> fCompressed = new HashSet<>();
+
+							HashMap<String, Long> fCompressed = new HashMap<>();
 							// handle propagation of compressed intermediates into functions
-							List<DataIdentifier> fArgs = fstmt.getInputParams();
-							for(int i = 0; i < fArgs.size(); i++)
-								if(compressed.contains(fop.getInput(i).getHopID()) ||
-									transientCompressed.contains(fop.getInput(i).getName()))
-									fCompressed.add(fArgs.get(i).getName());
+
+							String[] ins = fop.getInputVariableNames();
+							for(int i = 0; i < ins.length; i++) {
+								final String name = ins[i];
+								final Long outsideID = fop.getInput(i).getHopID();
+								if(compressed.contains(outsideID))
+									fCompressed.put(name, outsideID);
+							}
+
 							WorkloadAnalyzer fa = new WorkloadAnalyzer(prog, compressed, fCompressed, transposed,
-								overlapping, transientOverlapping);
+								overlapping, treeLookup);
 							fa.createWorkloadTree(n, fsb, prog, fStack);
-							List<DataIdentifier> fOut = fstmt.getOutputParams();
 							String[] outs = fop.getOutputVariableNames();
-							for(int i = 0; i < outs.length; i++)
-								if(fCompressed.contains(fOut.get(i).getName())) {
-									transientCompressed.add(outs[i]);
-								}
+							for(int i = 0; i < outs.length; i++) {
+								Long id = fCompressed.get(outs[i]);
+								if(id != null)
+									transientCompressed.put(outs[i], id);
+							}
 							fStack.remove(fop.getFunctionKey());
 						}
 					}
@@ -325,10 +329,9 @@ public class WorkloadAnalyzer {
 
 		// map statement block propagation to hop propagation
 		if(HopRewriteUtils.isData(hop, OpOpData.PERSISTENTREAD, OpOpData.TRANSIENTREAD) &&
-			transientCompressed.contains(hop.getName())) {
+			transientCompressed.containsKey(hop.getName())) {
 			compressed.add(hop.getHopID());
-			if(transientOverlapping.contains(hop.getName()))
-				overlapping.add(hop.getHopID());
+			treeLookup.put(hop.getHopID(), treeLookup.get(transientCompressed.get(hop.getName())));
 		}
 
 		if(LOG.isTraceEnabled()) {
@@ -338,37 +341,52 @@ public class WorkloadAnalyzer {
 
 		// collect operations on compressed intermediates or inputs
 		// if any input is compressed we collect this hop as a compressed operation
-		if(hop.getInput().stream().anyMatch(h -> compressed.contains(h.getHopID()))) {
-
-			if(isCompressedOp(hop)) {
-				Op o = createOp(hop);
-				parent.addOp(o);
-				if(o.isCompressedOutput())
-					compressed.add(hop.getHopID());
-			}
-			else if(HopRewriteUtils.isData(hop, OpOpData.TRANSIENTWRITE)) {
-				Hop in = hop.getInput().get(0);
-				if(compressed.contains(hop.getHopID()) || compressed.contains(in.getHopID()) ||
-					transientCompressed.contains(in.getName())) {
-					transientCompressed.add(hop.getName());
-				}
-				if(overlapping.contains(hop.getHopID()) || overlapping.contains(in.getHopID()) ||
-					transientOverlapping.contains(in.getName())) {
-					transientOverlapping.add(hop.getName());
-				}
-			}
-		}
+		if(hop.getInput().stream().anyMatch(h -> compressed.contains(h.getHopID())))
+			createOp(hop, parent);
 
 		visited.add(hop);
 	}
 
-	private Op createOp(Hop hop) {
+	private void createOp(Hop hop, AWTreeNode parent) {
 		if(hop.getDataType().isMatrix()) {
-			if(hop instanceof ReorgOp && ((ReorgOp) hop).getOp() == ReOrgOp.TRANS) {
+			Op o = null;
+			if(HopRewriteUtils.isData(hop, OpOpData.PERSISTENTREAD, OpOpData.TRANSIENTREAD)) {
+				return;
+			}
+			else if(HopRewriteUtils.isData(hop, OpOpData.TRANSIENTWRITE, OpOpData.PERSISTENTWRITE)) {
+				transientCompressed.put(hop.getName(), hop.getInput(0).getHopID());
+				compressed.add(hop.getHopID());
+				o = new OpMetadata(hop, hop.getInput(0));
+				if(isOverlapping(hop.getInput(0)))
+					o.setOverlapping();
+			}
+			else if(hop instanceof ReorgOp && ((ReorgOp) hop).getOp() == ReOrgOp.TRANS) {
 				transposed.add(hop.getHopID());
 				compressed.add(hop.getHopID());
-				transientCompressed.add(hop.getName());
-				return new OpMetadata(hop);
+				// hack add to transient compressed since the decompression is marking the parents.
+				transientCompressed.put(hop.getName(), hop.getHopID());
+				// transientCompressed.add(hop.getName());
+				o = new OpMetadata(hop, hop.getInput(0));
+				if(isOverlapping(hop.getInput(0)))
+					o.setOverlapping();
+			}
+			else if(hop instanceof AggUnaryOp) {
+				if((isOverlapping(hop.getInput().get(0)) &&
+					!HopRewriteUtils.isAggUnaryOp(hop, AggOp.SUM, AggOp.MEAN)) ||
+					HopRewriteUtils.isAggUnaryOp(hop, AggOp.TRACE)) {
+					setDecompressionOnAllInputs(hop, parent);
+					return;
+				}
+				else {
+					o = new OpNormal(hop, false);
+				}
+			}
+			else if(hop instanceof UnaryOp && !HopRewriteUtils.isUnary(hop, OpOp1.MULT2, OpOp1.MINUS1_MULT,
+				OpOp1.MINUS_RIGHT, OpOp1.CAST_AS_MATRIX)) {
+				if(isOverlapping(hop.getInput(0))) {
+					treeLookup.get(hop.getInput(0).getHopID()).setDecompressing();
+					return;
+				}
 			}
 			else if(hop instanceof AggBinaryOp) {
 				AggBinaryOp agbhop = (AggBinaryOp) hop;
@@ -376,90 +394,168 @@ public class WorkloadAnalyzer {
 				boolean transposedLeft = transposed.contains(in.get(0).getHopID());
 				boolean transposedRight = transposed.contains(in.get(1).getHopID());
 				boolean left = compressed.contains(in.get(0).getHopID()) ||
-					transientCompressed.contains(in.get(0).getName());
+					transientCompressed.containsKey(in.get(0).getName());
 				boolean right = compressed.contains(in.get(1).getHopID()) ||
-					transientCompressed.contains(in.get(1).getName());
+					transientCompressed.containsKey(in.get(1).getName());
 				OpSided ret = new OpSided(hop, left, right, transposedLeft, transposedRight);
-				if(ret.isRightMM()) {
-					// HashSet<Long> overlapping2 = new HashSet<>();
-					// overlapping2.add(hop.getHopID());
-					// WorkloadAnalyzer overlappingAnalysis = new WorkloadAnalyzer(prog, overlapping2);
-					// WTreeRoot r = overlappingAnalysis.createWorkloadTree(hop);
 
-					// CostEstimatorBuilder b = new CostEstimatorBuilder(r);
-					// if(LOG.isTraceEnabled())
-					// 	LOG.trace("Workload for overlapping: " + r + "\n" + b);
-
-					// if(b.shouldUseOverlap())
+				if(ret.isRightMM()) {
 					overlapping.add(hop.getHopID());
-					// else {
-					// 	decompressHops.add(hop);
-					// 	ret.setOverlappingDecompression(true);
-					// }
+					ret.setOverlapping();
+					if(!ret.isCompressedOutput())
+						ret.setDecompressing();
 				}
 
-				return ret;
-			}
-			else if(HopRewriteUtils.isBinary(hop, OpOp2.CBIND)) {
-				ArrayList<Hop> in = hop.getInput();
-				if(isOverlapping(in.get(0)) || isOverlapping(in.get(1)))
-					overlapping.add(hop.getHopID());
-				// CBind is in worst case decompressing, but can be compressing the other side if it is trivially compressable.
-				// to make the optimizer correct we need to mark this operation as decompressing, since it is the worst possible outcome.
-				// Currently we dont optimize for operations that are located past a cbind.
-				return new OpDecompressing(hop);
-			}
-			else if(HopRewriteUtils.isBinary(hop, OpOp2.RBIND)) {
-				ArrayList<Hop> in = hop.getInput();
-				if(isOverlapping(in.get(0)) || isOverlapping(in.get(1)))
-					return new OpOverlappingDecompress(hop);
-				else
-					return new OpDecompressing(hop);
+				o = ret;
+
 			}
-			else if(HopRewriteUtils.isBinaryMatrixScalarOperation(hop) ||
-				HopRewriteUtils.isBinaryMatrixRowVectorOperation(hop)) {
-				ArrayList<Hop> in = hop.getInput();
-				if(isOverlapping(in.get(0)) || isOverlapping(in.get(1)))
-					overlapping.add(hop.getHopID());
+			else if(hop instanceof BinaryOp) {
+				if(HopRewriteUtils.isBinary(hop, OpOp2.CBIND)) {
+					ArrayList<Hop> in = hop.getInput();
+					o = new OpNormal(hop, true);
+					if(isOverlapping(in.get(0)) || isOverlapping(in.get(1))) {
+						overlapping.add(hop.getHopID());
+						o.setOverlapping();
+					}
+					// assume that CBind have to decompress, but only such that it also have the compressed version
+					// available. Therefore add a new OpNormal, set to decompressing.
+					o.setDecompressing();
+				}
+				else if(HopRewriteUtils.isBinary(hop, OpOp2.RBIND)) {
+					setDecompressionOnAllInputs(hop, parent);
+					return;
+				}
+				// shortcut instead of comparing to MatrixScalar or RowVector.
+				else if(hop.getInput(1).getDim1() == 1 || hop.getInput(1).isScalar() || hop.getInput(0).isScalar()) {
+
+					ArrayList<Hop> in = hop.getInput();
+					final boolean ol0 = isOverlapping(in.get(0));
+					final boolean ol1 = isOverlapping(in.get(1));
+					final boolean ol = ol0 || ol1;
+					if(ol && HopRewriteUtils.isBinary(hop, OpOp2.PLUS, OpOp2.MULT, OpOp2.DIV, OpOp2.MINUS)) {
+						overlapping.add(hop.getHopID());
+						o = new OpNormal(hop, true);
+						o.setOverlapping();
+					}
+					else if(ol) {
+						treeLookup.get(in.get(0).getHopID()).setDecompressing();
+						return;
+					}
+					else {
+						o = new OpNormal(hop, true);
+					}
+					if(!HopRewriteUtils.isBinarySparseSafe(hop))
+						o.setDensifying();
+
+				}
+				else if(HopRewriteUtils.isBinaryMatrixMatrixOperation(hop) ||
+					HopRewriteUtils.isBinaryMatrixColVectorOperation(hop) ||
+					HopRewriteUtils.isBinaryMatrixMatrixOperationWithSharedInput(hop)) {
+					setDecompressionOnAllInputs(hop, parent);
+					return;
+				}
+				else {
+					String ex = "Setting decompressed because input Binary Op is unknown, please add the case to WorkloadAnalyzer:\n"
+						+ Explain.explain(hop);
+					LOG.warn(ex);
+					setDecompressionOnAllInputs(hop, parent);
+				}
 
-				return new OpNormal(hop, true);
 			}
 			else if(hop instanceof IndexingOp) {
 				IndexingOp idx = (IndexingOp) hop;
 				final boolean isOverlapping = isOverlapping(hop.getInput(0));
 				final boolean fullColumn = HopRewriteUtils.isFullColumnIndexing(idx);
-				if(fullColumn && isOverlapping)
-					overlapping.add(hop.getHopID());
 
-				if(fullColumn)
-					return new OpNormal(hop, RewriteCompressedReblock.satisfiesSizeConstraintsForCompression(hop));
-				else
-					return new OpDecompressing(hop);
+				if(fullColumn) {
+					o = new OpNormal(hop, RewriteCompressedReblock.satisfiesSizeConstraintsForCompression(hop));
+					if(isOverlapping) {
+						overlapping.add(hop.getHopID());
+						o.setOverlapping();
+					}
+				}
+				else {
+					// This decompression is a little different, since it does not decompress the entire matrix
+					// but only a sub part. therefore create a new op node and set it to decompressing.
+					o = new OpNormal(hop, false);
+					o.setDecompressing();
+				}
 			}
-			else if(HopRewriteUtils.isBinaryMatrixMatrixOperation(hop) ||
-				HopRewriteUtils.isBinaryMatrixColVectorOperation(hop)) {
-				ArrayList<Hop> in = hop.getInput();
-				if(isOverlapping(in.get(0)) || isOverlapping(in.get(1)))
-					return new OpOverlappingDecompress(hop);
-
-				return new OpDecompressing(hop);
+			else if(HopRewriteUtils.isTernary(hop, OpOp3.MINUS_MULT, OpOp3.PLUS_MULT, OpOp3.QUANTILE, OpOp3.CTABLE)) {
+				setDecompressionOnAllInputs(hop, parent);
+				return;
 			}
+			else if(HopRewriteUtils.isTernary(hop, OpOp3.IFELSE)) {
+				final Hop o1 = hop.getInput(1);
+				final Hop o2 = hop.getInput(2);
+				if(isCompressed(o1) && isCompressed(o2)) {
+					o = new OpMetadata(hop, o1);
+					if(isOverlapping(o1) || isOverlapping(o2))
+						o.setOverlapping();
+				}
+				else if(isCompressed(o1)) {
+					o = new OpMetadata(hop, o1);
+					if(isOverlapping(o1))
+						o.setOverlapping();
+				}
+				else if(isCompressed(o2)) {
+					o = new OpMetadata(hop, o2);
+					if(isOverlapping(o2))
+						o.setOverlapping();
+				}
+				else {
+					setDecompressionOnAllInputs(hop, parent);
+				}
+			}
+			else if(hop instanceof ParameterizedBuiltinOp) {
+				setDecompressionOnAllInputs(hop, parent);
+				return;
+			}
+			else
+				throw new DMLCompressionException("Unknown Hop: " + Explain.explain(hop));
+
+			o = o != null ? o : new OpNormal(hop, RewriteCompressedReblock.satisfiesSizeConstraintsForCompression(hop));
+			treeLookup.put(hop.getHopID(), o);
+			parent.addOp(o);
 
-			// if the output size also qualifies for compression, we propagate this status
-			// return new OpNormal(hop, RewriteCompressedReblock.satisfiesSizeConstraintsForCompression(hop));
-			return new OpNormal(hop, RewriteCompressedReblock.satisfiesSizeConstraintsForCompression(hop));
+			if(o.isCompressedOutput())
+				compressed.add(hop.getHopID());
+		}
+		else {
+			parent.addOp(new OpNormal(hop, false));
 		}
-		else
-			return new OpNormal(hop, false);
 	}
 
-	private boolean isOverlapping(Hop hop) {
-		return overlapping.contains(hop.getHopID()) || transientOverlapping.contains(hop.getName());
+	private boolean isCompressed(Hop hop) {
+		return compressed.contains(hop.getHopID());
+	}
+
+	private void setDecompressionOnAllInputs(Hop hop, AWTreeNode parent) {
+		if(parent instanceof WTreeRoot)
+			((WTreeRoot) parent).setDecompressing();
+		for(Hop h : hop.getInput()) {
+			Op ol = treeLookup.get(h.getHopID());
+			if(ol != null) {
+				while(ol instanceof OpMetadata) {
+					// go up through operations and mark the first known as decompressing.
+					// The first known usually is the root of the work tree.
+					Op oln = treeLookup.get(((OpMetadata) ol).getParent().getHopID());
+					if(oln == null)
+						break;
+					else
+						ol = oln;
+				}
+				ol.setDecompressing();
+			}
+		}
 	}
 
-	private static boolean isCompressedOp(Hop hop) {
-		return !(HopRewriteUtils.isData(hop, OpOpData.PERSISTENTREAD, // all, but data ops
-			OpOpData.TRANSIENTREAD, OpOpData.TRANSIENTWRITE));
+	private boolean isOverlapping(Hop hop) {
+		Op o = treeLookup.get(hop.getHopID());
+		if(o != null)
+			return o.isOverlapping();
+		else
+			return false;
 	}
 
 	private static boolean isNoOp(Hop hop) {
diff --git a/src/main/java/org/apache/sysds/runtime/controlprogram/context/SparkExecutionContext.java b/src/main/java/org/apache/sysds/runtime/controlprogram/context/SparkExecutionContext.java
index faef2c7..ca3f69c 100644
--- a/src/main/java/org/apache/sysds/runtime/controlprogram/context/SparkExecutionContext.java
+++ b/src/main/java/org/apache/sysds/runtime/controlprogram/context/SparkExecutionContext.java
@@ -1065,6 +1065,7 @@ public class SparkExecutionContext extends ExecutionContext
 
 			//copy blocks one-at-a-time into output matrix block
 			long aNnz = 0;
+			boolean firstCompressed = true;
 			for( Tuple2<MatrixIndexes,MatrixBlock> keyval : list )
 			{
 				//unpack index-block pair
@@ -1079,7 +1080,12 @@ public class SparkExecutionContext extends ExecutionContext
 				
 				//handle compressed blocks (decompress for robustness)
 				if( block instanceof CompressedMatrixBlock ){
-					block = ((CompressedMatrixBlock)block).decompress(InfrastructureAnalyzer.getLocalParallelism());
+					if(firstCompressed){
+						// with warning.
+						block =((CompressedMatrixBlock)block).getUncompressed("Spark RDD block to MatrixBlock Decompressing");
+						firstCompressed = false;
+					}else
+						block = ((CompressedMatrixBlock)block).decompress(InfrastructureAnalyzer.getLocalParallelism());
 				}
 
 				//append block
@@ -1281,13 +1287,13 @@ public class SparkExecutionContext extends ExecutionContext
 		return out;
 	}
 
-	// @SuppressWarnings("unchecked")
+	@SuppressWarnings("unchecked")
 	public static long writeMatrixRDDtoHDFS( RDDObject rdd, String path, FileFormat fmt )
 	{
 		JavaPairRDD<MatrixIndexes,MatrixBlock> lrdd = (JavaPairRDD<MatrixIndexes, MatrixBlock>) rdd.getRDD();
 		InputOutputInfo oinfo = InputOutputInfo.get(DataType.MATRIX, fmt);
 		
-		// if compression is enabled decompress all blocks before writing to disk TEMPORARY MODIFICATION UNTILL MATRIXBLOCK IS MERGED WITH COMPRESSEDMATRIXBLOCK
+		// if compression is enabled decompress all blocks before writing to disk to ensure type of MatrixBlock.
 		if(ConfigurationManager.isCompressionEnabled())
 			lrdd = lrdd.mapValues(new DeCompressionSPInstruction.DeCompressionFunction());
 
diff --git a/src/main/java/org/apache/sysds/runtime/instructions/cp/SpoofCPInstruction.java b/src/main/java/org/apache/sysds/runtime/instructions/cp/SpoofCPInstruction.java
index 97047a4..15d35b7 100644
--- a/src/main/java/org/apache/sysds/runtime/instructions/cp/SpoofCPInstruction.java
+++ b/src/main/java/org/apache/sysds/runtime/instructions/cp/SpoofCPInstruction.java
@@ -86,8 +86,7 @@ public class SpoofCPInstruction extends ComputationCPInstruction {
 				MatrixBlock mb = ec.getMatrixInput(input.getName());
 				//FIXME fused codegen operators already support compressed main inputs 
 				if(mb instanceof CompressedMatrixBlock){
-					LOG.warn("Spoof instruction decompressed matrix");
-					mb = ((CompressedMatrixBlock) mb).decompress(_numThreads);
+					mb = ((CompressedMatrixBlock) mb).getUncompressed("Spoof instruction");
 				}
 				inputs.add(mb);
 			}
diff --git a/src/main/java/org/apache/sysds/runtime/matrix/data/LibMatrixBincell.java b/src/main/java/org/apache/sysds/runtime/matrix/data/LibMatrixBincell.java
index 6d53ff7..f949c6c 100644
--- a/src/main/java/org/apache/sysds/runtime/matrix/data/LibMatrixBincell.java
+++ b/src/main/java/org/apache/sysds/runtime/matrix/data/LibMatrixBincell.java
@@ -359,10 +359,10 @@ public class LibMatrixBincell {
 
 	public static void isValidDimensionsBinary(MatrixBlock m1, MatrixBlock m2)
 	{
-		int rlen1 = m1.rlen;
-		int clen1 = m1.clen;
-		int rlen2 = m2.rlen;
-		int clen2 = m2.clen;
+		final int rlen1 = m1.rlen;
+		final int clen1 = m1.clen;
+		final int rlen2 = m2.rlen;
+		final int clen2 = m2.clen;
 		
 		//currently we support three major binary cellwise operations:
 		//1) MM (where both dimensions need to match)
@@ -376,7 +376,7 @@ public class LibMatrixBincell {
 
 		if( !isValid ) {
 			throw new RuntimeException("Block sizes are not matched for binary " +
-					"cell operations: " + m1.rlen + "x" + m1.clen + " vs " + m2.rlen + "x" + m2.clen);
+					"cell operations: " + rlen1 + "x" + clen1 + " vs " + rlen2 + "x" + clen2);
 		}
 	}
 
diff --git a/src/main/java/org/apache/sysds/runtime/matrix/data/MatrixBlock.java b/src/main/java/org/apache/sysds/runtime/matrix/data/MatrixBlock.java
index 6c7cb0a..07afc4c 100644
--- a/src/main/java/org/apache/sysds/runtime/matrix/data/MatrixBlock.java
+++ b/src/main/java/org/apache/sysds/runtime/matrix/data/MatrixBlock.java
@@ -522,7 +522,6 @@ public class MatrixBlock extends MatrixValue implements CacheBlock, Externalizab
 		return isEmptyBlock(true);
 	}
 	
-	
 	public boolean isEmptyBlock(boolean safe)
 	{
 		boolean ret = ( sparse && sparseBlock==null ) || ( !sparse && denseBlock==null );
@@ -2955,37 +2954,31 @@ public class MatrixBlock extends MatrixValue implements CacheBlock, Externalizab
 	}
 	
 	public MatrixBlock ternaryOperations(TernaryOperator op, MatrixBlock m2, MatrixBlock m3, MatrixBlock ret) {
-		if(m2 instanceof CompressedMatrixBlock)
-			m2 = ((CompressedMatrixBlock) m2).getUncompressed("Ternay Operator arg2 " + op.fn.getClass().getSimpleName());
-		if(m3 instanceof CompressedMatrixBlock)
-			m3 = ((CompressedMatrixBlock) m3).getUncompressed("Ternay Operator arg3 " + op.fn.getClass().getSimpleName());
-
+		
 		//prepare inputs
-		final boolean s1 = (rlen==1 && clen==1);
-		final boolean s2 = (m2.rlen==1 && m2.clen==1);
-		final boolean s3 = (m3.rlen==1 && m3.clen==1);
+		final int r1 = getNumRows();
+		final int r2 = m2.getNumRows();
+		final int r3 = m3.getNumRows();
+		final int c1 = getNumColumns();
+		final int c2 = m2.getNumColumns();
+		final int c3 = m3.getNumColumns();
+		final boolean s1 = (r1 == 1 && c1 == 1);
+		final boolean s2 = (r2 == 1 && c2 == 1);
+		final boolean s3 = (r3 == 1 && c3 == 1);
 		final double d1 = s1 ? quickGetValue(0, 0) : Double.NaN;
 		final double d2 = s2 ? m2.quickGetValue(0, 0) : Double.NaN;
 		final double d3 = s3 ? m3.quickGetValue(0, 0) : Double.NaN;
-		final int m = Math.max(Math.max(rlen, m2.rlen), m3.rlen);
-		final int n = Math.max(Math.max(clen, m2.clen), m3.clen);
+		final int m = Math.max(Math.max(r1, r2), r3);
+		final int n = Math.max(Math.max(c1, c2), c3);
 		final long nnz = nonZeros;
 		
-		//error handling 
-		if( (!s1 && (rlen != m || clen != n))
-			|| (!s2 && (m2.rlen != m || m2.clen != n))
-			|| (!s3 && (m3.rlen != m || m3.clen != n)) ) {
-			throw new DMLRuntimeException("Block sizes are not matched for ternary cell operations: "
-				+ rlen + "x" + clen + " vs " + m2.rlen + "x" + m2.clen + " vs " + m3.rlen + "x" + m3.clen);
-		}
+		ternaryOperationCheck(s1, s2, s3, m, r1, r2, r3, n, c1, c2, c3);
 		
 		//prepare result
-		boolean sparseOutput = (op.fn instanceof PlusMultiply || op.fn instanceof MinusMultiply)?
-			evalSparseFormatInMemory(m, n, (s1?m*n*(d1!=0?1:0):getNonZeros())
-				+ Math.min(s2?m*n:m2.getNonZeros(), s3?m*n:m3.getNonZeros())) : false;
-		ret.reset(m, n, sparseOutput);
-		
 		if( op.fn instanceof IfElse && (s1 || nnz==0 || nnz==(long)m*n) ) {
+			
+			ret.reset(m, n, false);
+			
 			//SPECIAL CASE for shallow-copy if-else
 			boolean expr = s1 ? (d1 != 0) : (nnz==(long)m*n);
 			MatrixBlock tmp = expr ? m2 : m3;
@@ -3003,24 +2996,55 @@ public class MatrixBlock extends MatrixValue implements CacheBlock, Externalizab
 				}
 			}
 		}
-		else if (s2 != s3 && (op.fn instanceof PlusMultiply || op.fn instanceof MinusMultiply) ) {
-			//SPECIAL CASE for sparse-dense combinations of common +* and -*
-			BinaryOperator bop = ((ValueFunctionWithConstant)op.fn).setOp2Constant(s2 ? d2 : d3);
-			if( op.getNumThreads() > 1 )
-				LibMatrixBincell.bincellOp(this, s2 ? m3 : m2, ret, bop, op.getNumThreads());
-			else
-				LibMatrixBincell.bincellOp(this, s2 ? m3 : m2, ret, bop);
-		}
-		else {
-			//DEFAULT CASE
-			LibMatrixTercell.tercellOp(this, m2, m3, ret, op);
+		else{
+			final boolean PM_Or_MM = (op.fn instanceof PlusMultiply || op.fn instanceof MinusMultiply);
 			
-			//ensure correct output representation
-			ret.examSparsity();
+			if(PM_Or_MM && ((s2 && d2 == 0) || (s3 && d3 == 0))) {
+				ret.copy(this);
+				return ret;
+			}
+			
+			final boolean sparseOutput = evalSparseFormatInMemory(m, n, (s1 ? m * n * (d1 != 0 ? 1 : 0) : getNonZeros()) +
+				Math.min(s2 ? m * n : m2.getNonZeros(), s3 ? m * n : m3.getNonZeros()));
+
+			if(m2 instanceof CompressedMatrixBlock)
+				m2 = ((CompressedMatrixBlock) m2)
+					.getUncompressed("Ternay Operator arg2 " + op.fn.getClass().getSimpleName());
+			if(m3 instanceof CompressedMatrixBlock)
+				m3 = ((CompressedMatrixBlock) m3)
+					.getUncompressed("Ternay Operator arg3 " + op.fn.getClass().getSimpleName());
+
+			ret.reset(m, n, sparseOutput);
+
+			if (s2 != s3 && (op.fn instanceof PlusMultiply || op.fn instanceof MinusMultiply) ) {
+				//SPECIAL CASE for sparse-dense combinations of common +* and -*
+				BinaryOperator bop = ((ValueFunctionWithConstant)op.fn).setOp2Constant(s2 ? d2 : d3);
+				if( op.getNumThreads() > 1 )
+					LibMatrixBincell.bincellOp(this, s2 ? m3 : m2, ret, bop, op.getNumThreads());
+				else
+					LibMatrixBincell.bincellOp(this, s2 ? m3 : m2, ret, bop);
+			}
+			else {
+				//DEFAULT CASE
+				LibMatrixTercell.tercellOp(this, m2, m3, ret, op);
+				
+				//ensure correct output representation
+				ret.examSparsity();
+			}
 		}
 		
 		return ret;
 	}
+
+	protected static void ternaryOperationCheck(boolean s1, boolean s2, boolean s3, int m, int r1, int r2, int r3, int n, int c1, int c2, int c3){
+		//error handling 
+		if( (!s1 && (r1 != m || c1 != n))
+		|| (!s2 && (r2 != m || c2 != n))
+		|| (!s3 && (r3 != m || c3 != n)) ) {
+			throw new DMLRuntimeException("Block sizes are not matched for ternary cell operations: "
+			+ r1 + "x" + c1 + " vs " + r2 + "x" + c2 + " vs " + r3 + "x" + c3);
+		}
+	}
 	
 	@Override
 	public void incrementalAggregate(AggregateOperator aggOp, MatrixValue correction, MatrixValue newWithCorrection, boolean deep) {
diff --git a/src/main/java/org/apache/sysds/runtime/util/DataConverter.java b/src/main/java/org/apache/sysds/runtime/util/DataConverter.java
index 6850a97..1339a68 100644
--- a/src/main/java/org/apache/sysds/runtime/util/DataConverter.java
+++ b/src/main/java/org/apache/sysds/runtime/util/DataConverter.java
@@ -260,7 +260,7 @@ public class DataConverter {
 		int cols = mb.getNumColumns();
 		double[][] ret = new double[rows][cols]; //0-initialized
 		if(mb instanceof CompressedMatrixBlock){
-			mb = ((CompressedMatrixBlock)mb).decompress();
+			mb = ((CompressedMatrixBlock)mb).getUncompressed("convert to Double Matrix");
 		}
 		if( mb.getNonZeros() > 0 ) {
 			if( mb.isInSparseFormat() ) {
diff --git a/src/test/java/org/apache/sysds/test/component/compress/AbstractCompressedUnaryTests.java b/src/test/java/org/apache/sysds/test/component/compress/AbstractCompressedUnaryTests.java
index 61968d8..ec969e3 100644
--- a/src/test/java/org/apache/sysds/test/component/compress/AbstractCompressedUnaryTests.java
+++ b/src/test/java/org/apache/sysds/test/component/compress/AbstractCompressedUnaryTests.java
@@ -249,8 +249,6 @@ public abstract class AbstractCompressedUnaryTests extends CompressedTestBase {
 			MatrixBlock ret1 = mb.aggregateUnaryOperations(auop, new MatrixBlock(), Math.max(rows, cols), null, inCP);
 			// matrix-vector compressed
 			MatrixBlock ret2 = cmb.aggregateUnaryOperations(auop, new MatrixBlock(), Math.max(rows, cols), null, inCP);
-			// LOG.error(ret1 + "\nvs\n" + ret2);
-			// LOG.error(cmb);
 			// compare result with input
 
 			assertTrue("dim 1 is not equal in compressed res  should be : " + ret1.getNumRows() + "  but is: "
diff --git a/src/test/java/org/apache/sysds/test/component/compress/CompressedMatrixTest.java b/src/test/java/org/apache/sysds/test/component/compress/CompressedMatrixTest.java
index a998a74..cc47036 100644
--- a/src/test/java/org/apache/sysds/test/component/compress/CompressedMatrixTest.java
+++ b/src/test/java/org/apache/sysds/test/component/compress/CompressedMatrixTest.java
@@ -38,7 +38,12 @@ import org.apache.sysds.runtime.compress.CompressionStatistics;
 import org.apache.sysds.runtime.compress.colgroup.AColGroup;
 import org.apache.sysds.runtime.compress.colgroup.AColGroup.CompressionType;
 import org.apache.sysds.runtime.functionobjects.KahanPlus;
+import org.apache.sysds.runtime.functionobjects.Minus;
+import org.apache.sysds.runtime.functionobjects.Minus1Multiply;
+import org.apache.sysds.runtime.functionobjects.MinusMultiply;
 import org.apache.sysds.runtime.functionobjects.Multiply;
+import org.apache.sysds.runtime.functionobjects.Plus;
+import org.apache.sysds.runtime.functionobjects.PlusMultiply;
 import org.apache.sysds.runtime.functionobjects.ReduceAll;
 import org.apache.sysds.runtime.matrix.data.LibMatrixCountDistinct;
 import org.apache.sysds.runtime.matrix.data.LibMatrixDatagen;
@@ -47,8 +52,12 @@ import org.apache.sysds.runtime.matrix.data.RandomMatrixGenerator;
 import org.apache.sysds.runtime.matrix.operators.AggregateOperator;
 import org.apache.sysds.runtime.matrix.operators.AggregateTernaryOperator;
 import org.apache.sysds.runtime.matrix.operators.AggregateUnaryOperator;
+import org.apache.sysds.runtime.matrix.operators.BinaryOperator;
 import org.apache.sysds.runtime.matrix.operators.CountDistinctOperator;
 import org.apache.sysds.runtime.matrix.operators.CountDistinctOperator.CountDistinctTypes;
+import org.apache.sysds.runtime.matrix.operators.RightScalarOperator;
+import org.apache.sysds.runtime.matrix.operators.ScalarOperator;
+import org.apache.sysds.runtime.matrix.operators.TernaryOperator;
 import org.apache.sysds.runtime.util.DataConverter;
 import org.apache.sysds.test.TestUtils;
 import org.apache.sysds.test.component.compress.TestConstants.MatrixTypology;
@@ -579,7 +588,7 @@ public class CompressedMatrixTest extends AbstractCompressedUnaryTests {
 	@Test
 	public void testAggregateTernaryOperation() {
 		try {
-			if(!(cmb instanceof CompressedMatrixBlock) || rows * cols > 10000)
+			if(!(cmb instanceof CompressedMatrixBlock) || rows * cols > 1000)
 				return;
 			CorrectionLocationType corr = CorrectionLocationType.LASTCOLUMN;
 			AggregateOperator agg = new AggregateOperator(0, KahanPlus.getKahanPlusFnObject(), corr);
@@ -603,6 +612,158 @@ public class CompressedMatrixTest extends AbstractCompressedUnaryTests {
 		}
 	}
 
+	@Test
+	public void testAggregateTernaryOperationZero() {
+		try {
+			if(!(cmb instanceof CompressedMatrixBlock) || rows * cols > 10000)
+				return;
+			CorrectionLocationType corr = CorrectionLocationType.LASTCOLUMN;
+			AggregateOperator agg = new AggregateOperator(0, KahanPlus.getKahanPlusFnObject(), corr);
+			AggregateTernaryOperator op = new AggregateTernaryOperator(Multiply.getMultiplyFnObject(), agg,
+				ReduceAll.getReduceAllFnObject());
+
+			int nrow = mb.getNumRows();
+			int ncol = mb.getNumColumns();
+
+			MatrixBlock m2 = new MatrixBlock(nrow, ncol, 0);
+			MatrixBlock m3 = new MatrixBlock(nrow, ncol, 14.0);
+
+			MatrixBlock ret1 = cmb.aggregateTernaryOperations(cmb, m2, m3, null, op, true);
+			MatrixBlock ret2 = mb.aggregateTernaryOperations(mb, m2, m3, null, op, true);
+
+			compareResultMatrices(ret2, ret1, 1);
+		}
+		catch(Exception e) {
+			e.printStackTrace();
+			throw new DMLRuntimeException(e);
+		}
+	}
+
+	@Test
+	public void testTernaryOperation() {
+		try {
+			if(!(cmb instanceof CompressedMatrixBlock) || rows * cols > 10000)
+				return;
+			TernaryOperator op = new TernaryOperator(PlusMultiply.getFnObject(), _k);
+
+			int nrow = mb.getNumRows();
+			int ncol = mb.getNumColumns();
+
+			MatrixBlock m2 = new MatrixBlock(1, 1, 0);
+			MatrixBlock m3 = new MatrixBlock(nrow, ncol, 14.0);
+			MatrixBlock ret1 = cmb.ternaryOperations(op, m2, m3, new MatrixBlock());
+			MatrixBlock ret2 = mb.ternaryOperations(op, m2, m3, new MatrixBlock());
+
+			compareResultMatrices(ret2, ret1, 1);
+		}
+		catch(Exception e) {
+			e.printStackTrace();
+			throw new DMLRuntimeException(e);
+		}
+	}
+
+	@Test
+	public void testBinaryEmptyScalarOp() {
+		try {
+			if(!(cmb instanceof CompressedMatrixBlock))
+				return;
+			BinaryOperator op = new BinaryOperator(Multiply.getMultiplyFnObject());
+
+			MatrixBlock m2 = new MatrixBlock(1, 1, 0);
+			MatrixBlock ret1 = cmb.binaryOperations(op, m2, new MatrixBlock());
+			ScalarOperator sop = new RightScalarOperator(op.fn, m2.getValue(0, 0), op.getNumThreads());
+			MatrixBlock ret2 = mb.scalarOperations(sop, new MatrixBlock());
+
+			compareResultMatrices(ret2, ret1, 1);
+		}
+		catch(Exception e) {
+			e.printStackTrace();
+			throw new DMLRuntimeException(e);
+		}
+	}
+
+	@Test
+	public void testBinaryEmptyMatrixMultiplicationOp() {
+		BinaryOperator op = new BinaryOperator(Multiply.getMultiplyFnObject());
+		testBinaryEmptyMatrixOp(op);
+	}
+
+	@Test
+	public void testBinaryEmptyMatrixMinusOp() {
+		BinaryOperator op = new BinaryOperator(Minus.getMinusFnObject());
+		testBinaryEmptyMatrixOp(op);
+	}
+
+	@Test
+	public void testBinaryEmptyMatrixPlusOp() {
+		BinaryOperator op = new BinaryOperator(Plus.getPlusFnObject());
+		testBinaryEmptyMatrixOp(op);
+	}
+
+	@Test
+	public void testBinaryEmptyMatrixMinusMultiplyOp() {
+		BinaryOperator op = MinusMultiply.getFnObject().setOp2Constant(42);
+		testBinaryEmptyMatrixOp(op);
+	}
+
+	@Test
+	public void testBinaryEmptyMatrixMinus1MultiplyOp() {
+		BinaryOperator op = new BinaryOperator(Minus1Multiply.getMinus1MultiplyFnObject());
+		testBinaryEmptyMatrixOp(op);
+	}
+
+	public void testBinaryEmptyMatrixOp(BinaryOperator op) {
+		try {
+			if(!(cmb instanceof CompressedMatrixBlock))
+				return;
+
+			MatrixBlock m2 = new MatrixBlock(cmb.getNumRows(), cmb.getNumColumns(), 0);
+			MatrixBlock ret1 = cmb.binaryOperations(op, m2, new MatrixBlock());
+			MatrixBlock ret2 = mb.binaryOperations(op, m2, new MatrixBlock());
+
+			compareResultMatrices(ret2, ret1, 1);
+		}
+		catch(Exception e) {
+			e.printStackTrace();
+			throw new DMLRuntimeException(e);
+		}
+	}
+
+	@Test
+	public void testBinaryEmptyRowVectorMultiplicationOp() {
+		BinaryOperator op = new BinaryOperator(Multiply.getMultiplyFnObject());
+		testBinaryEmptyRowVectorOp(op);
+	}
+
+	@Test
+	public void testBinaryEmptyRowVectorMinusOp() {
+		BinaryOperator op = new BinaryOperator(Minus.getMinusFnObject());
+		testBinaryEmptyRowVectorOp(op);
+	}
+
+	@Test
+	public void testBinaryEmptyRowVectorPlusOp() {
+		BinaryOperator op = new BinaryOperator(Plus.getPlusFnObject());
+		testBinaryEmptyRowVectorOp(op);
+	}
+
+	public void testBinaryEmptyRowVectorOp(BinaryOperator op) {
+		try {
+			if(!(cmb instanceof CompressedMatrixBlock))
+				return;
+
+			MatrixBlock m2 = new MatrixBlock(1, cmb.getNumColumns(), 0);
+			MatrixBlock ret1 = cmb.binaryOperations(op, m2, new MatrixBlock());
+			MatrixBlock ret2 = mb.binaryOperations(op, m2, new MatrixBlock());
+
+			compareResultMatrices(ret2, ret1, 1);
+		}
+		catch(Exception e) {
+			e.printStackTrace();
+			throw new DMLRuntimeException(e);
+		}
+	}
+
 	private static long getJolSize(CompressedMatrixBlock cmb, CompressionStatistics cStat) {
 		Layouter l = new HotSpotLayouter(new X86_64_DataModel());
 		long jolEstimate = 0;
diff --git a/src/test/java/org/apache/sysds/test/component/compress/CompressedTestBase.java b/src/test/java/org/apache/sysds/test/component/compress/CompressedTestBase.java
index c291235..ef8441e 100644
--- a/src/test/java/org/apache/sysds/test/component/compress/CompressedTestBase.java
+++ b/src/test/java/org/apache/sysds/test/component/compress/CompressedTestBase.java
@@ -1282,14 +1282,23 @@ public abstract class CompressedTestBase extends TestBase {
 	}
 
 	protected void compareResultMatrices(MatrixBlock expected, MatrixBlock result, double toleranceMultiplier) {
+		compareDimensions(expected, result);
 		if(expected instanceof CompressedMatrixBlock)
 			expected = ((CompressedMatrixBlock) expected).decompress();
 		if(result instanceof CompressedMatrixBlock)
 			result = ((CompressedMatrixBlock) result).decompress();
+		
+		compareDimensions(expected, result);
+			
 
 		// compare result with input
 		double[][] d1 = DataConverter.convertToDoubleMatrix(expected);
 		double[][] d2 = DataConverter.convertToDoubleMatrix(result);
 		compareResultMatrices(d1, d2, toleranceMultiplier);
 	}
+
+	protected static void compareDimensions(MatrixBlock expected, MatrixBlock result){
+		assertEquals(expected.getNumRows(), result.getNumRows());
+		assertEquals(expected.getNumColumns(), result.getNumColumns());
+	}
 }
diff --git a/src/test/java/org/apache/sysds/test/component/compress/workload/WorkloadTest.java b/src/test/java/org/apache/sysds/test/component/compress/workload/WorkloadTest.java
index 9422e58..f1682a7 100644
--- a/src/test/java/org/apache/sysds/test/component/compress/workload/WorkloadTest.java
+++ b/src/test/java/org/apache/sysds/test/component/compress/workload/WorkloadTest.java
@@ -47,6 +47,7 @@ public class WorkloadTest {
 
 	private static final String basePath = "src/test/scripts/component/compress/workload/";
 	private static final String testFile = "src/test/resources/component/compress/1-1.csv";
+	private static final String yFile = "src/test/resources/component/compress/1-1_y.csv";
 
 	@Parameterized.Parameter(0)
 	public int scans;
@@ -83,17 +84,13 @@ public class WorkloadTest {
 		tests.add(new Object[] {0, 0, 0, 0, 0, 0, 1, 0, false, false, "sum.dml", args});
 		tests.add(new Object[] {0, 0, 0, 0, 0, 0, 1, 0, false, false, "mean.dml", args});
 		tests.add(new Object[] {0, 0, 0, 0, 0, 0, 1, 1, false, false, "plus.dml", args});
-		tests.add(new Object[] {0, 1, 0, 0, 0, 0, 1, 0, false, false, "sliceCols.dml", args});
+		tests.add(new Object[] {0, 0, 0, 0, 0, 0, 2, 0, false, false, "sliceCols.dml", args});
 		tests.add(new Object[] {0, 0, 0, 0, 0, 0, 2, 0, false, false, "sliceIndex.dml", args});
 		tests.add(new Object[] {0, 0, 0, 1, 0, 0, 0, 0, false, false, "leftMult.dml", args});
 		tests.add(new Object[] {0, 0, 0, 0, 1, 0, 1, 0, false, false, "rightMult.dml", args});
 		tests.add(new Object[] {0, 0, 0, 1, 0, 0, 0, 0, false, false, "TLeftMult.dml", args});
 
-		// https://issues.apache.org/jira/browse/SYSTEMDS-3025 Transposed layout.
-		// (the t right mult here would be much faster if a transposed layout is allowed.)
-		// Also the decompression is not detected.
-		// nr 8:
-		tests.add(new Object[] {0, 0, 0, 0, 1, 0, 1, 0, false, false, "TRightMult.dml", args});
+		tests.add(new Object[] {0, 0, 1, 0, 1, 0, 0, 0, false, false, "TRightMult.dml", args});
 
 		// Loops:
 		tests.add(new Object[] {0, 0, 0, 11, 0, 0, 0, 0, true, false, "loop/leftMult.dml", args});
@@ -104,22 +101,24 @@ public class WorkloadTest {
 
 		// Builtins:
 		// nr 11:
-		tests.add(new Object[] {0, 0, 0, 0, 0, 0, 7, 0, true, false, "functions/scale.dml", args});
+		tests.add(new Object[] {0, 0, 0, 0, 0, 0, 6, 0, true, false, "functions/scale.dml", args});
 		tests.add(new Object[] {0, 0, 0, 0, 0, 0, 5, 0, true, true, "functions/scale.dml", args});
-		tests.add(new Object[] {0, 0, 0, 0, 0, 0, 8, 0, true, false, "functions/scale_continued.dml", args});
+		tests.add(new Object[] {0, 0, 0, 0, 0, 0, 6, 0, true, false, "functions/scale_continued.dml", args});
 		tests.add(new Object[] {0, 0, 0, 0, 0, 0, 6, 0, true, true, "functions/scale_continued.dml", args});
 		tests.add(new Object[] {0, 0, 0, 0, 0, 0, 2, 0, false, true, "functions/scale_onlySide.dml", args});
-		tests.add(new Object[] {0, 0, 0, 0, 0, 0, 8, 0, true, false, "functions/scale_onlySide.dml", args});
+		tests.add(new Object[] {0, 0, 0, 0, 0, 0, 6, 0, true, false, "functions/scale_onlySide.dml", args});
 
-		tests.add(new Object[] {0, 0, 0, 0, 1, 1, 9, 0, true, false, "functions/pca.dml", args});
-		tests.add(new Object[] {0, 0, 0, 0, 1, 1, 6, 0, true, true, "functions/pca.dml", args});
+		tests.add(new Object[] {0, 0, 0, 0, 1, 1, 8, 0, true, false, "functions/pca.dml", args});
+		tests.add(new Object[] {0, 0, 0, 0, 1, 1, 5, 0, true, true, "functions/pca.dml", args});
 
 		args = new HashMap<>();
 		args.put("$1", testFile);
 		args.put("$2", "FALSE");
 		args.put("$3", "0");
 
-		tests.add(new Object[] {0, 1, 0, 1, 1, 1, 6, 0, true, false, "functions/lmDS.dml", args});
+		// no recompile
+		tests.add(new Object[] {0, 1, 1, 1, 1, 1, 6, 0, true, false, "functions/lmDS.dml", args});
+		// with recompile
 		tests.add(new Object[] {0, 0, 0, 1, 0, 1, 0, 0, true, true, "functions/lmDS.dml", args});
 		tests.add(new Object[] {0, 0, 0, 1, 10, 10, 1, 0, true, true, "functions/lmCG.dml", args});
 
@@ -127,30 +126,34 @@ public class WorkloadTest {
 		args.put("$1", testFile);
 		args.put("$2", "TRUE");
 		args.put("$3", "0");
-		tests.add(new Object[] {0, 0, 1, 1, 1, 1, 0, 0, true, true, "functions/lmDS.dml", args});
+		tests.add(new Object[] {0, 1, 1, 1, 1, 1, 0, 0, true, true, "functions/lmDS.dml", args});
 		tests.add(new Object[] {0, 0, 1, 1, 11, 10, 1, 0, true, true, "functions/lmCG.dml", args});
 
 		args = new HashMap<>();
 		args.put("$1", testFile);
 		args.put("$2", "TRUE");
 		args.put("$3", "1");
-		tests.add(new Object[] {0, 1, 0, 0, 0, 0, 1, 0, false, true, "functions/lmDS.dml", args});
+		tests.add(new Object[] {0, 2, 1, 1, 1, 1, 1, 0, true, true, "functions/lmDS.dml", args});
 		tests.add(new Object[] {0, 1, 1, 1, 11, 10, 2, 0, true, true, "functions/lmCG.dml", args});
 
 		args = new HashMap<>();
 		args.put("$1", testFile);
 		args.put("$2", "TRUE");
 		args.put("$3", "2");
-		tests.add(new Object[] {0, 1, 0, 0, 0, 0, 1, 0, false, true, "functions/lmDS.dml", args});
-		tests.add(new Object[] {0, 1, 1, 1, 11, 10, 2, 0, true, true, "functions/lmCG.dml", args});
+		tests.add(new Object[] {0, 2, 1, 1, 1, 1, 3, 0, true, true, "functions/lmDS.dml", args});
+		tests.add(new Object[] {0, 1, 1, 1, 11, 10, 4, 0, true, true, "functions/lmCG.dml", args});
 
 		args = new HashMap<>();
 		args.put("$1", testFile);
 		args.put("$2", "FALSE");
-		// Currently l2svm detects that decompression is needed after right mult
 		tests.add(new Object[] {0, 0, 10, 11, 10, 0, 1, 0, true, true, "functions/l2svm.dml", args});
 
 		args = new HashMap<>();
+		args.put("$1", yFile);
+		args.put("$2", "FALSE");
+		tests.add(new Object[] {0, 1, 0, 1, 0, 0, 10, 0, true, true, "functions/l2svm_Y.dml", args});
+
+		args = new HashMap<>();
 		args.put("$1", testFile);
 		args.put("$2", "100");
 		args.put("$3", "16");
@@ -184,9 +187,10 @@ public class WorkloadTest {
 		}
 	}
 
-	private void verify(WTreeRoot wtr, InstructionTypeCounter itc, CostEstimatorBuilder ceb, String name, Map<String, String> args) {
+	private void verify(WTreeRoot wtr, InstructionTypeCounter itc, CostEstimatorBuilder ceb, String name,
+		Map<String, String> args) {
 
-		String errorString = wtr + "\n" + itc + " \n " + name + "  -- " + args +  "\n";
+		String errorString = wtr + "\n" + itc + " \n " + name + "  -- " + args + "\n";
 		Assert.assertEquals(errorString + "scans:", scans, itc.getScans());
 		Assert.assertEquals(errorString + "decompressions", decompressions, itc.getDecompressions());
 		Assert.assertEquals(errorString + "overlappingDecompressions", overlappingDecompressions,
@@ -214,7 +218,6 @@ public class WorkloadTest {
 			String filePath = basePath + name;
 			String dmlScript = DMLScript.readDMLScript(isFile, filePath);
 			return ParserFactory.createParser().parse(DMLOptions.defaultOptions.filePath, dmlScript, args);
-
 		}
 		catch(Exception e) {
 			throw new DMLRuntimeException("Error in parsing", e);
diff --git a/src/test/java/org/apache/sysds/test/component/frame/DataCorruptionTest.java b/src/test/java/org/apache/sysds/test/component/frame/DataCorruptionTest.java
index 316e062..51fa497 100644
--- a/src/test/java/org/apache/sysds/test/component/frame/DataCorruptionTest.java
+++ b/src/test/java/org/apache/sysds/test/component/frame/DataCorruptionTest.java
@@ -90,7 +90,7 @@ public class DataCorruptionTest
 				assertTrue("Row "+i+" was marked with typos, but it has not been changed.", checkTypo);
 			}
 		}
-		System.out.println("Test typos: number of changed rows: " + numch);
+		// Test typos: number of changed rows: 
 		assertEquals("The number of changed rows is not approx. 20%", 0.2, numch/Xp.getNumRows(), 0.05);
 	}
 	
@@ -114,7 +114,7 @@ public class DataCorruptionTest
 				assertTrue("Row "+i+" was marked with missing values, but it has not been changed.", dropped>0);
 			}
 		}
-		System.out.println("Test missing: number of changed rows: " + numch);
+		// Test missing: number of changed rows:
 		assertEquals("The number of changed rows is not approx. 20%", 0.2, numch/Xp.getNumRows(), 0.05);
 	}
 	
@@ -147,7 +147,7 @@ public class DataCorruptionTest
 				assertTrue("Row "+i+" was marked with outliers, but it has not been changed.", checkOut);
 			}
 		}
-		System.out.println("Test outliers: number of changed rows: " + numch);
+		// Test outliers: number of changed rows:
 		assertEquals("The number of changed rows is not approx. 20%", 0.2, numch/Xp.getNumRows(), 0.05);
 	}
 	
@@ -192,7 +192,7 @@ public class DataCorruptionTest
 				assertTrue("Row "+i+" was marked with outliers, but it has not been changed.",checkSwap);
 			}
 		}
-		System.out.println("Test swap: number of changed rows: " + numch);
+		// Test swap: number of changed rows:
 		assertEquals("The number of changed rows is not approx. 20%", 0.2, numch/changed.getNumRows(), 0.05);
 		
 	}
diff --git a/src/test/java/org/apache/sysds/test/functions/codegen/RowAggTmplTest.java b/src/test/java/org/apache/sysds/test/functions/codegen/RowAggTmplTest.java
index 540b07b..5ae3196 100644
--- a/src/test/java/org/apache/sysds/test/functions/codegen/RowAggTmplTest.java
+++ b/src/test/java/org/apache/sysds/test/functions/codegen/RowAggTmplTest.java
@@ -25,14 +25,15 @@ import java.util.HashMap;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.sysds.common.Types.ExecMode;
-import org.apache.sysds.hops.OptimizerUtils;
 import org.apache.sysds.common.Types.ExecType;
+import org.apache.sysds.hops.OptimizerUtils;
 import org.apache.sysds.lops.RightIndex;
 import org.apache.sysds.runtime.matrix.data.MatrixValue.CellIndex;
 import org.apache.sysds.test.AutomatedTestBase;
 import org.apache.sysds.test.TestConfiguration;
 import org.apache.sysds.test.TestUtils;
 import org.junit.Assert;
+import org.junit.Ignore;
 import org.junit.Test;
 
 public class RowAggTmplTest extends AutomatedTestBase
@@ -357,6 +358,9 @@ public class RowAggTmplTest extends AutomatedTestBase
 	}
 	
 	@Test
+	@Ignore
+	// Since adding the rewrite (simplyfyMMCBindZeroVector) CodeGen is unable to
+	// combine the instructions.
 	public void testCodegenRowAggRewrite18CP() {
 		testCodegenIntegration( TEST_NAME18, true, ExecType.CP );
 	}
diff --git a/src/test/java/org/apache/sysds/test/functions/compress/CompressInstruction.java b/src/test/java/org/apache/sysds/test/functions/compress/CompressInstruction.java
index 929c202..9498e77 100644
--- a/src/test/java/org/apache/sysds/test/functions/compress/CompressInstruction.java
+++ b/src/test/java/org/apache/sysds/test/functions/compress/CompressInstruction.java
@@ -95,7 +95,6 @@ public class CompressInstruction extends AutomatedTestBase {
 			programArgs = new String[] {"-stats", "100", "-nvargs", "cols=" + cols, "rows=" + rows,
 				"sparsity=" + sparsity, "min=" + min, "max= " + max};
 			runTest(null);
-			// LOG.error(runTest(null));
 
 		}
 		catch(Exception e) {
diff --git a/src/test/java/org/apache/sysds/test/functions/compress/CompressInstructionRewrite.java b/src/test/java/org/apache/sysds/test/functions/compress/CompressInstructionRewrite.java
index c005115..b1697e7 100644
--- a/src/test/java/org/apache/sysds/test/functions/compress/CompressInstructionRewrite.java
+++ b/src/test/java/org/apache/sysds/test/functions/compress/CompressInstructionRewrite.java
@@ -21,11 +21,8 @@ package org.apache.sysds.test.functions.compress;
 
 import static org.junit.Assert.assertTrue;
 
-import java.io.ByteArrayOutputStream;
 import java.io.File;
 
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
 import org.apache.sysds.common.Types;
 import org.apache.sysds.common.Types.ExecType;
 import org.apache.sysds.test.AutomatedTestBase;
@@ -37,7 +34,7 @@ import org.junit.Assert;
 import org.junit.Test;
 
 public class CompressInstructionRewrite extends AutomatedTestBase {
-	private static final Log LOG = LogFactory.getLog(CompressInstructionRewrite.class.getName());
+	// private static final Log LOG = LogFactory.getLog(CompressInstructionRewrite.class.getName());
 
 	private String TEST_CONF = "SystemDS-config-compress-cost.xml";
 	private File TEST_CONF_FILE = new File(SCRIPT_DIR + getTestDir(), TEST_CONF);
@@ -91,12 +88,12 @@ public class CompressInstructionRewrite extends AutomatedTestBase {
 
 	@Test
 	public void testCompressInstruction_07() {
-		compressTest(6, 6000, 0.2, ExecType.CP, 0, 5, 0, 1, "07");
+		compressTest(10, 6000, 0.2, ExecType.CP, 0, 3, 0, 1, "07");
 	}
 
 	@Test
 	public void testCompressInstruction_08() {
-		compressTest(6, 6000, 0.2, ExecType.CP, 0, 5, 0, 1, "08");
+		compressTest(10, 6000, 0.2, ExecType.CP, 0, 3, 0, 1, "08");
 	}
 
 	@Test
@@ -109,7 +106,6 @@ public class CompressInstructionRewrite extends AutomatedTestBase {
 		compressTest(1, 1000, 1.0, ExecType.CP, 5, 5, 0, 0, "10");
 	}
 
-
 	public void compressTest(int cols, int rows, double sparsity, ExecType instType, int min, int max,
 		int decompressionCountExpected, int compressionCountsExpected, String name) {
 
@@ -122,16 +118,13 @@ public class CompressInstructionRewrite extends AutomatedTestBase {
 			programArgs = new String[] {"-explain", "-stats", "100", "-nvargs", "cols=" + cols, "rows=" + rows,
 				"sparsity=" + sparsity, "min=" + min, "max= " + max};
 
-			ByteArrayOutputStream stdout = runTest(null);
-
-			if(LOG.isDebugEnabled())
-				LOG.debug(stdout);
+			String stdout = runTest(null).toString();
 
 			int decompressCount = DMLCompressionStatistics.getDecompressionCount();
 			long compressionCount = Statistics.getCPHeavyHitterCount("compress");
 
-			Assert.assertEquals(compressionCountsExpected, compressionCount);
-			Assert.assertEquals(decompressionCountExpected, decompressCount);
+			Assert.assertEquals(stdout, compressionCountsExpected, compressionCount);
+			Assert.assertEquals(stdout, decompressionCountExpected, decompressCount);
 			if(decompressionCountExpected > 0)
 				Assert.assertTrue(heavyHittersContainsString("decompress", decompressionCountExpected));
 		}
diff --git a/src/test/java/org/apache/sysds/test/functions/compress/CompressRewriteSpark.java b/src/test/java/org/apache/sysds/test/functions/compress/CompressRewriteSpark.java
index fe3cda5..dc5d205 100644
--- a/src/test/java/org/apache/sysds/test/functions/compress/CompressRewriteSpark.java
+++ b/src/test/java/org/apache/sysds/test/functions/compress/CompressRewriteSpark.java
@@ -23,8 +23,6 @@ import static org.junit.Assert.assertTrue;
 
 import java.io.File;
 
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
 import org.apache.sysds.common.Types;
 import org.apache.sysds.common.Types.ExecMode;
 import org.apache.sysds.test.AutomatedTestBase;
@@ -33,8 +31,10 @@ import org.apache.sysds.test.TestUtils;
 import org.junit.Assert;
 import org.junit.Test;
 
+
+@net.jcip.annotations.NotThreadSafe
 public class CompressRewriteSpark extends AutomatedTestBase {
-	private static final Log LOG = LogFactory.getLog(CompressRewriteSpark.class.getName());
+	// private static final Log LOG = LogFactory.getLog(CompressRewriteSpark.class.getName());
 
 	private static final String dataPath = "src/test/scripts/functions/compress/densifying/";
 	private final static String TEST_DIR = "functions/compress/";
@@ -66,27 +66,24 @@ public class CompressRewriteSpark extends AutomatedTestBase {
 		compressTest(ExecMode.HYBRID, "02", "large.ijv");
 	}
 
-
-	@Test 
-	public void testCompressionInstruction_colmean(){
-		compressTest(ExecMode.HYBRID,"submean", "large.ijv");
+	@Test
+	public void testCompressionInstruction_colmean() {
+		compressTest(ExecMode.HYBRID, "submean", "large.ijv");
 	}
 
-
-	@Test 
-	public void testCompressionInstruction_scale(){
-		compressTest(ExecMode.HYBRID,"scale", "large.ijv");
+	@Test
+	public void testCompressionInstruction_scale() {
+		compressTest(ExecMode.HYBRID, "scale", "large.ijv");
 	}
 
-
-	@Test 
-	public void testCompressionInstruction_seq_large(){
-		compressTest(ExecMode.HYBRID,"seq", "large.ijv");
+	@Test
+	public void testCompressionInstruction_seq_large() {
+		compressTest(ExecMode.HYBRID, "seq", "large.ijv");
 	}
 
-	@Test 
-	public void testCompressionInstruction_pca_large(){
-		compressTest(ExecMode.HYBRID,"pca", "large.ijv");
+	@Test
+	public void testCompressionInstruction_pca_large() {
+		compressTest(ExecMode.HYBRID, "pca", "large.ijv");
 	}
 
 	public void compressTest(ExecMode instType, String name, String data) {
@@ -98,12 +95,14 @@ public class CompressRewriteSpark extends AutomatedTestBase {
 
 			fullDMLScriptName = SCRIPT_DIR + "/" + getTestDir() + "compress_" + name + ".dml";
 
-			programArgs = new String[] {"-stats", "100", "-explain", "-args", dataPath + data};
+			programArgs = new String[] {"-stats", "100","-explain", "-args", dataPath + data};
 
-			LOG.debug(runTest(null));
+			String out = runTest(null).toString();
 
-			Assert.assertTrue(!heavyHittersContainsString("sp_compress"));
-			Assert.assertTrue(!heavyHittersContainsString("sp_+"));
+			Assert.assertTrue(out + "\nShould not containing spark compression instruction",
+				!heavyHittersContainsString("sp_compress"));
+			Assert.assertTrue(out + "\nShould not contain spark instruction on compressed input",
+				!heavyHittersContainsString("sp_+"));
 
 		}
 		catch(Exception e) {
diff --git a/src/test/java/org/apache/sysds/test/functions/compress/configuration/CompressBase.java b/src/test/java/org/apache/sysds/test/functions/compress/configuration/CompressBase.java
index c466e17..d38bb32 100644
--- a/src/test/java/org/apache/sysds/test/functions/compress/configuration/CompressBase.java
+++ b/src/test/java/org/apache/sysds/test/functions/compress/configuration/CompressBase.java
@@ -21,8 +21,6 @@ package org.apache.sysds.test.functions.compress.configuration;
 
 import static org.junit.Assert.assertTrue;
 
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
 import org.apache.sysds.common.Types;
 import org.apache.sysds.common.Types.ExecType;
 import org.apache.sysds.runtime.meta.MatrixCharacteristics;
@@ -34,7 +32,7 @@ import org.apache.sysds.utils.Statistics;
 import org.junit.Assert;
 
 public abstract class CompressBase extends AutomatedTestBase {
-	private static final Log LOG = LogFactory.getLog(CompressBase.class.getName());
+	// private static final Log LOG = LogFactory.getLog(CompressBase.class.getName());
 
 	protected abstract String getTestClassDir();
 
@@ -49,7 +47,7 @@ public abstract class CompressBase extends AutomatedTestBase {
 	}
 
 	public void runTest(int rows, int cols, int decompressCount, int compressCount, ExecType ex, String name) {
-		compressTest(rows, cols, 1.0, ex, 1, 10, 1.4, decompressCount, compressCount, name);
+		compressTest(rows, cols, 1.0, ex, 1, 5, 1.4, decompressCount, compressCount, name);
 	}
 
 	public void compressTest(int rows, int cols, double sparsity, ExecType instType, int min, int max, double delta,
@@ -64,19 +62,17 @@ public abstract class CompressBase extends AutomatedTestBase {
 			writeInputMatrixWithMTD("A", A, false, new MatrixCharacteristics(rows, cols, 1000, rows * cols));
 
 			fullDMLScriptName = SCRIPT_DIR + "/functions/compress/compress_" + name + ".dml";
+			programArgs = new String[] {"-stats", "100", "-nvargs", "A=" + input("A")};
 
-			// programArgs = new String[] {"-stats", "100" , "-explain", "-nvargs", "A=" + input("A")};
-			programArgs = new String[] {"-stats", "100",  "-nvargs", "A=" + input("A")};
-
-			LOG.debug(runTest(null));
+			String out = runTest(null).toString();
 
 			int decompressCount = DMLCompressionStatistics.getDecompressionCount();
 			long compressionCount = (instType == ExecType.SPARK) ? Statistics
 				.getCPHeavyHitterCount("sp_compress") : Statistics.getCPHeavyHitterCount("compress");
 			DMLCompressionStatistics.reset();
 
-			Assert.assertEquals("Expected compression count   : ", compressionCount, compressionCountsExpected);
-			Assert.assertEquals("Expected Decompression count : ", decompressionCountExpected, decompressCount);
+			Assert.assertEquals(out + "\ncompression count   wrong : ", compressionCount, compressionCountsExpected);
+			Assert.assertEquals(out + "\nDecompression count wrong : ", decompressionCountExpected, decompressCount);
 
 		}
 		catch(Exception e) {
diff --git a/src/test/java/org/apache/sysds/test/functions/compress/configuration/CompressCost.java b/src/test/java/org/apache/sysds/test/functions/compress/configuration/CompressCost.java
deleted file mode 100644
index a64e8de..0000000
--- a/src/test/java/org/apache/sysds/test/functions/compress/configuration/CompressCost.java
+++ /dev/null
@@ -1,70 +0,0 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License.  You may obtain a copy of the License at
- *
- *   http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-package org.apache.sysds.test.functions.compress.configuration;
-
-import java.io.File;
-
-import org.apache.sysds.common.Types.ExecType;
-import org.junit.Test;
-
-public class CompressCost extends CompressBase {
-
-	public String TEST_NAME = "compress";
-	public String TEST_DIR = "functions/compress/cost/";
-	public String TEST_CLASS_DIR = TEST_DIR + CompressCost.class.getSimpleName() + "/";
-	private String TEST_CONF = "SystemDS-config-compress-cost.xml";
-	private File TEST_CONF_FILE = new File(SCRIPT_DIR + TEST_DIR, TEST_CONF);
-
-	protected String getTestClassDir() {
-		return TEST_CLASS_DIR;
-	}
-
-	protected String getTestName() {
-		return TEST_NAME;
-	}
-
-	protected String getTestDir() {
-		return TEST_DIR;
-	}
-
-	@Test
-	public void testTranspose() {
-		runTest(100, 20, 0, 0, ExecType.CP, "transpose");
-	}
-
-	@Test
-	public void testSum() {
-		runTest(100, 20, 0, 0, ExecType.CP, "sum");
-	}
-
-	@Test
-	public void testRowAggregate() {
-		runTest(100, 20, 0, 0, ExecType.CP, "row_min");
-	}
-
-	/**
-	 * Override default configuration with custom test configuration to ensure scratch space and local temporary
-	 * directory locations are also updated.
-	 */
-	@Override
-	protected File getConfigTemplateFile() {
-		return TEST_CONF_FILE;
-	}
-}
diff --git a/src/test/java/org/apache/sysds/test/functions/compress/configuration/CompressForce.java b/src/test/java/org/apache/sysds/test/functions/compress/configuration/CompressForce.java
index 84be096..dc5b17f 100644
--- a/src/test/java/org/apache/sysds/test/functions/compress/configuration/CompressForce.java
+++ b/src/test/java/org/apache/sysds/test/functions/compress/configuration/CompressForce.java
@@ -151,11 +151,47 @@ public class CompressForce extends CompressBase {
 	}
 
 	@Test
+	public void testMatrixMultRightSum_Larger_CP() {
+		runTest(1500, 11, 0, 1, ExecType.CP, "mmr_sum");
+	}
+
+	@Test
 	public void testMatrixMultRightSum_Larger_SP() {
 		runTest(1500, 11, 0, 1, ExecType.SPARK, "mmr_sum");
 	}
 
 	@Test
+	public void testMatrixMultRightSumPlus_Larger_CP() {
+		runTest(1500, 11, 0, 1, ExecType.CP, "mmr_sum_plus");
+	}
+
+	@Test
+	public void testMatrixMultRightSumPlus_Larger_SP() {
+		runTest(1500, 11, 0, 1, ExecType.SPARK, "mmr_sum_plus");
+	}
+
+	@Test
+	public void testMatrixMultRightSumPlusOnOverlap_Larger_CP() {
+		runTest(1500, 11, 0, 1, ExecType.CP, "mmr_sum_plus_2");
+	}
+
+	@Test
+	public void testMatrixMultRightSumPlusOnOverlap_Larger_SP() {
+		// be aware that with multiple blocks it is likely that the small blocks
+		// initially compress, but is to large for overlapping state will decompress.
+		// In this test it does not decompress
+		runTest(1010, 11, 0, 1, ExecType.SPARK, "mmr_sum_plus_2");
+	}
+
+	@Test
+	public void testMatrixMultRightSumPlusOnOverlapDecompress_Larger_SP() {
+		// be aware that with multiple blocks it is likely that the small blocks
+		// initially compress, but is to large for overlapping state therefor will decompress.
+		// In this test it decompress the second small block but keeps the first in overlapping state.
+		runTest(1110, 30, 1, 1, ExecType.SPARK, "mmr_sum_plus_2");
+	}
+
+	@Test
 	public void testMatrixMultLeftSum_CP() {
 		runTest(1500, 1, 0, 1, ExecType.CP, "mml_sum");
 	}
diff --git a/src/test/java/org/apache/sysds/test/functions/compress/configuration/CompressLossy.java b/src/test/java/org/apache/sysds/test/functions/compress/configuration/CompressLossy.java
deleted file mode 100644
index 68da2e5..0000000
--- a/src/test/java/org/apache/sysds/test/functions/compress/configuration/CompressLossy.java
+++ /dev/null
@@ -1,52 +0,0 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License.  You may obtain a copy of the License at
- *
- *   http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-package org.apache.sysds.test.functions.compress.configuration;
-
-import java.io.File;
-
-public class CompressLossy extends CompressForce {
-
-	public String TEST_NAME = "compress";
-	public String TEST_DIR = "functions/compress/force/";
-	public String TEST_CLASS_DIR = TEST_DIR + CompressLossy.class.getSimpleName() + "/";
-	private String TEST_CONF = "SystemDS-config-compress-lossy.xml";
-	private File TEST_CONF_FILE = new File(SCRIPT_DIR + TEST_DIR, TEST_CONF);
-
-	protected String getTestClassDir() {
-		return TEST_CLASS_DIR;
-	}
-
-	protected String getTestName() {
-		return TEST_NAME;
-	}
-
-	protected String getTestDir() {
-		return TEST_DIR;
-	}
-
-	/**
-	 * Override default configuration with custom test configuration to ensure scratch space and local temporary
-	 * directory locations are also updated.
-	 */
-	@Override
-	protected File getConfigTemplateFile() {
-		return TEST_CONF_FILE;
-	}
-}
diff --git a/src/test/java/org/apache/sysds/test/functions/compress/configuration/CompressLossyCost.java b/src/test/java/org/apache/sysds/test/functions/compress/configuration/CompressLossyCost.java
deleted file mode 100644
index e99e791..0000000
--- a/src/test/java/org/apache/sysds/test/functions/compress/configuration/CompressLossyCost.java
+++ /dev/null
@@ -1,52 +0,0 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License.  You may obtain a copy of the License at
- *
- *   http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-package org.apache.sysds.test.functions.compress.configuration;
-
-import java.io.File;
-
-public class CompressLossyCost extends CompressCost {
-
-	public String TEST_NAME = "compress";
-	public String TEST_DIR = "functions/compress/cost";
-	public String TEST_CLASS_DIR = TEST_DIR + CompressLossyCost.class.getSimpleName() + "/";
-	private String TEST_CONF = "SystemDS-config-compress-cost-lossy.xml";
-	private File TEST_CONF_FILE = new File(SCRIPT_DIR + TEST_DIR, TEST_CONF);
-
-	protected String getTestClassDir() {
-		return TEST_CLASS_DIR;
-	}
-
-	protected String getTestName() {
-		return TEST_NAME;
-	}
-
-	protected String getTestDir() {
-		return TEST_DIR;
-	}
-
-	/**
-	 * Override default configuration with custom test configuration to ensure scratch space and local temporary
-	 * directory locations are also updated.
-	 */
-	@Override
-	protected File getConfigTemplateFile() {
-		return TEST_CONF_FILE;
-	}
-}
diff --git a/src/test/java/org/apache/sysds/test/functions/compress/workload/WorkloadAlgorithmTest.java b/src/test/java/org/apache/sysds/test/functions/compress/workload/WorkloadAlgorithmTest.java
index af05bdc..c35b209 100644
--- a/src/test/java/org/apache/sysds/test/functions/compress/workload/WorkloadAlgorithmTest.java
+++ b/src/test/java/org/apache/sysds/test/functions/compress/workload/WorkloadAlgorithmTest.java
@@ -44,6 +44,7 @@ public class WorkloadAlgorithmTest extends AutomatedTestBase {
 	private final static String TEST_NAME4 = "WorkloadAnalysisSliceLine";
 	private final static String TEST_NAME5 = "WorkloadAnalysisSliceFinder";
 	private final static String TEST_NAME6 = "WorkloadAnalysisLmCG";
+	private final static String TEST_NAME7 = "WorkloadAnalysisL2SVM";
 	private final static String TEST_DIR = "functions/compress/workload/";
 	private final static String TEST_CLASS_DIR = TEST_DIR + WorkloadAnalysisTest.class.getSimpleName() + "/";
 
@@ -69,6 +70,7 @@ public class WorkloadAlgorithmTest extends AutomatedTestBase {
 		addTestConfiguration(TEST_NAME4, new TestConfiguration(TEST_CLASS_DIR, TEST_NAME4, new String[] {"B"}));
 		addTestConfiguration(TEST_NAME5, new TestConfiguration(TEST_CLASS_DIR, TEST_NAME5, new String[] {"B"}));
 		addTestConfiguration(TEST_NAME6, new TestConfiguration(TEST_CLASS_DIR, TEST_NAME6, new String[] {"B"}));
+		addTestConfiguration(TEST_NAME7, new TestConfiguration(TEST_CLASS_DIR, TEST_NAME7, new String[] {"B"}));
 	}
 
 	@Test
@@ -126,6 +128,11 @@ public class WorkloadAlgorithmTest extends AutomatedTestBase {
 		runWorkloadAnalysisTest(TEST_NAME6, ExecMode.SINGLE_NODE, 2, false);
 	}
 
+	@Test
+	public void testL2SVMCP() {
+		runWorkloadAnalysisTest(TEST_NAME7, ExecMode.SINGLE_NODE, 2, false);
+	}
+
 	// private void runWorkloadAnalysisTest(String testname, ExecMode mode, int compressionCount) {
 	private void runWorkloadAnalysisTest(String testname, ExecMode mode, int compressionCount, boolean intermediates) {
 		ExecMode oldPlatform = setExecMode(mode);
@@ -137,8 +144,7 @@ public class WorkloadAlgorithmTest extends AutomatedTestBase {
 
 			String HOME = SCRIPT_DIR + TEST_DIR;
 			fullDMLScriptName = HOME + testname + ".dml";
-			programArgs = new String[] {"-stats", "20", "-args", input("X"), input("y"),
-				output("B")};
+			programArgs = new String[] {"-stats", "20", "-args", input("X"), input("y"), output("B")};
 
 			writeInputMatrixWithMTD("X", X, false);
 			writeInputMatrixWithMTD("y", y, false);
@@ -153,7 +159,7 @@ public class WorkloadAlgorithmTest extends AutomatedTestBase {
 			Assert.assertEquals("Assert that the compression counts expeted matches actual: " + compressionCount
 				+ " vs " + actualCompressionCount, compressionCount, actualCompressionCount);
 			if(compressionCount > 0)
-				Assert.assertTrue(mode == ExecMode.SINGLE_NODE || mode == ExecMode.HYBRID ?  heavyHittersContainsString(
+				Assert.assertTrue(mode == ExecMode.SINGLE_NODE || mode == ExecMode.HYBRID ? heavyHittersContainsString(
 					"compress") : heavyHittersContainsString("sp_compress"));
 			if(!testname.equals(TEST_NAME4))
 				Assert.assertFalse(heavyHittersContainsString("m_scale"));
diff --git a/src/test/java/org/apache/sysds/test/functions/compress/workload/WorkloadAnalysisTest.java b/src/test/java/org/apache/sysds/test/functions/compress/workload/WorkloadAnalysisTest.java
index a9c2853..f1efd34 100644
--- a/src/test/java/org/apache/sysds/test/functions/compress/workload/WorkloadAnalysisTest.java
+++ b/src/test/java/org/apache/sysds/test/functions/compress/workload/WorkloadAnalysisTest.java
@@ -45,15 +45,14 @@ public class WorkloadAnalysisTest extends AutomatedTestBase {
 		addTestConfiguration(TEST_NAME2, new TestConfiguration(TEST_CLASS_DIR, TEST_NAME2, new String[] {"B"}));
 	}
 
-
-	@Test 
-	public void testLeftMultiplicationLoop(){
+	@Test
+	public void testLeftMultiplicationLoop() {
 		runWorkloadAnalysisTest(TEST_NAME1, ExecMode.HYBRID, 1);
 	}
 
 	@Test
-	public void testRightMultiplicationLoop(){
-		runWorkloadAnalysisTest(TEST_NAME2, ExecMode.HYBRID,1);
+	public void testRightMultiplicationLoop() {
+		runWorkloadAnalysisTest(TEST_NAME2, ExecMode.HYBRID, 1);
 	}
 
 	private void runWorkloadAnalysisTest(String testname, ExecMode mode, int compressionCount) {
diff --git a/src/test/java/org/apache/sysds/test/functions/rewrite/RewriteMMCBindZeroVector.java b/src/test/java/org/apache/sysds/test/functions/rewrite/RewriteMMCBindZeroVector.java
index 1cc1cca..6a8bfd7 100644
--- a/src/test/java/org/apache/sysds/test/functions/rewrite/RewriteMMCBindZeroVector.java
+++ b/src/test/java/org/apache/sysds/test/functions/rewrite/RewriteMMCBindZeroVector.java
@@ -58,25 +58,35 @@ public class RewriteMMCBindZeroVector extends AutomatedTestBase {
 
 	@Test
 	public void testNoRewritesCP() {
-		testRewrite(TEST_NAME1, false, ExecType.CP, 100, 3, 10);
+		testRewrite(TEST_NAME1, false, ExecType.CP, 100, 3, 10, false);
 	}
 
 	@Test
 	public void testNoRewritesSP() {
-		testRewrite(TEST_NAME1, false, ExecType.SPARK, 100, 3, 10);
+		testRewrite(TEST_NAME1, false, ExecType.SPARK, 100, 3, 10, false);
 	}
 
 	@Test
 	public void testRewritesCP() {
-		testRewrite(TEST_NAME1, true, ExecType.CP, 100, 3, 10);
+		testRewrite(TEST_NAME1, true, ExecType.CP, 100, 3, 10, true);
 	}
 
 	@Test
 	public void testRewritesSP() {
-		testRewrite(TEST_NAME1, true, ExecType.SPARK, 100, 3, 10);
+		testRewrite(TEST_NAME1, true, ExecType.SPARK, 100, 3, 10, true);
 	}
 
-	private void testRewrite(String testname, boolean rewrites, ExecType et, int leftRows, int rightCols, int shared) {
+	@Test
+	public void testRewritesCP_ButToSmall() {
+		testRewrite(TEST_NAME1, true, ExecType.CP, 100, 10, 55, false);
+	}
+
+	@Test
+	public void testRewritesSP_ButToSmall() {
+		testRewrite(TEST_NAME1, true, ExecType.SPARK, 100, 10, 55, false);
+	}
+
+	private void testRewrite(String testname, boolean rewrites, ExecType et, int leftRows, int rightCols, int shared, boolean rewriteShouldBeExecuted) {
 		ExecMode platformOld = rtplatform;
 		switch(et) {
 			case SPARK:
@@ -100,7 +110,7 @@ public class RewriteMMCBindZeroVector extends AutomatedTestBase {
 
 			String HOME = SCRIPT_DIR + TEST_DIR;
 			fullDMLScriptName = HOME + testname + ".dml";
-			programArgs = new String[] {"-explain", "-stats", "-args", input("X"), input("Y"),
+			programArgs = new String[] {"-explain", "hops","-stats", "-args", input("X"), input("Y"),
 				output("R")};
 			fullRScriptName = HOME + testname + ".R";
 			rCmd = getRCmd(inputDir(), expectedDir());
@@ -114,20 +124,20 @@ public class RewriteMMCBindZeroVector extends AutomatedTestBase {
 			String out = runTest(null).toString();
 
 			for(String line : out.split("\n")) {
-				if(rewrites) {
-					if(line.contains("append"))
+				if(rewrites && rewriteShouldBeExecuted) {
+					if(line.contains("b(cbind)"))
 						break;
-					else if(line.contains("ba+*"))
+					else if(line.contains("ba(+*)"))
 						fail(
-							"invalid execution matrix multiplication is done before append, therefore the rewrite did not tricker.\n\n"
+							"invalid execution matrix multiplication is done before b(cbind), therefore the rewrite did not tricker.\n\n"
 								+ out);
 				}
 				else {
-					if(line.contains("ba+*"))
+					if(line.contains("ba(+*)"))
 						break;
-					else if(line.contains("append"))
+					else if(line.contains("b(cbind)"))
 						fail(
-							"invalid execution append was done before multiplication, therefore the rewrite did tricker when not allowed.\n\n"
+							"invalid execution b(cbind) was done before multiplication, therefore the rewrite did tricker when not allowed.\n\n"
 								+ out);
 				}
 
diff --git a/src/test/resources/component/compress/1-1_y.csv b/src/test/resources/component/compress/1-1_y.csv
new file mode 100644
index 0000000..56a6051
--- /dev/null
+++ b/src/test/resources/component/compress/1-1_y.csv
@@ -0,0 +1 @@
+1
\ No newline at end of file
diff --git a/src/test/resources/component/compress/1-1_y.csv.mtd b/src/test/resources/component/compress/1-1_y.csv.mtd
new file mode 100644
index 0000000..2db0d5e
--- /dev/null
+++ b/src/test/resources/component/compress/1-1_y.csv.mtd
@@ -0,0 +1,8 @@
+{  
+    "data_type": "matrix",
+    "value_type": "double",  
+    "rows": 1000000,
+    "cols": 1,
+    "nnz": 1,
+    "format": "csv"
+}
diff --git a/src/test/resources/component/compress/README.md b/src/test/resources/component/compress/README.md
index 183e4d6..a6669df 100644
--- a/src/test/resources/component/compress/README.md
+++ b/src/test/resources/component/compress/README.md
@@ -19,5 +19,5 @@ limitations under the License.
 
 # Test files
 
-It is intensional that the mtd file says that the file is 1 million rows, and the actual file is 1 row.
+It is intensional that the mtd files says that the file is 1 million rows, and the actual file is 1 row.
 Since the tests using this file is intended for simulating the workload, not actually executing the script.
diff --git a/src/test/scripts/functions/compress/compress_mmr_sum.dml b/src/test/scripts/component/compress/workload/functions/l2svm_Y.dml
similarity index 87%
copy from src/test/scripts/functions/compress/compress_mmr_sum.dml
copy to src/test/scripts/component/compress/workload/functions/l2svm_Y.dml
index a3bedfb..c270663 100644
--- a/src/test/scripts/functions/compress/compress_mmr_sum.dml
+++ b/src/test/scripts/component/compress/workload/functions/l2svm_Y.dml
@@ -19,8 +19,8 @@
 #
 #-------------------------------------------------------------
 
-x = read($A)
-v = rand(rows=ncol(x), cols=10, min=0.0, max=1.0, seed= 13);
-r = x %*% v  + 1
-s = sum(r)
-print(s)
+b = read($1)
+A = rand(rows= nrow(b), cols = 10, min = -1, max = 1)
+b = round(b)
+m = l2svm(X=A ,Y=b, verbose=$2)
+print(mean(m))
diff --git a/src/test/scripts/functions/compress/compress_mmr_sum.dml b/src/test/scripts/functions/compress/compress_mmr_sum.dml
index a3bedfb..b46ef4b 100644
--- a/src/test/scripts/functions/compress/compress_mmr_sum.dml
+++ b/src/test/scripts/functions/compress/compress_mmr_sum.dml
@@ -21,6 +21,6 @@
 
 x = read($A)
 v = rand(rows=ncol(x), cols=10, min=0.0, max=1.0, seed= 13);
-r = x %*% v  + 1
+r = x %*% v
 s = sum(r)
 print(s)
diff --git a/src/test/scripts/functions/compress/compress_mmr_sum.dml b/src/test/scripts/functions/compress/compress_mmr_sum_plus.dml
similarity index 98%
copy from src/test/scripts/functions/compress/compress_mmr_sum.dml
copy to src/test/scripts/functions/compress/compress_mmr_sum_plus.dml
index a3bedfb..506ffbe 100644
--- a/src/test/scripts/functions/compress/compress_mmr_sum.dml
+++ b/src/test/scripts/functions/compress/compress_mmr_sum_plus.dml
@@ -21,6 +21,6 @@
 
 x = read($A)
 v = rand(rows=ncol(x), cols=10, min=0.0, max=1.0, seed= 13);
-r = x %*% v  + 1
+r = (x + 1) %*% v
 s = sum(r)
 print(s)
diff --git a/src/test/scripts/functions/compress/compress_mmr_sum.dml b/src/test/scripts/functions/compress/compress_mmr_sum_plus_2.dml
similarity index 98%
copy from src/test/scripts/functions/compress/compress_mmr_sum.dml
copy to src/test/scripts/functions/compress/compress_mmr_sum_plus_2.dml
index a3bedfb..162309a 100644
--- a/src/test/scripts/functions/compress/compress_mmr_sum.dml
+++ b/src/test/scripts/functions/compress/compress_mmr_sum_plus_2.dml
@@ -21,6 +21,6 @@
 
 x = read($A)
 v = rand(rows=ncol(x), cols=10, min=0.0, max=1.0, seed= 13);
-r = x %*% v  + 1
+r = (x %*% v) + 1
 s = sum(r)
 print(s)
diff --git a/src/test/scripts/functions/compress/compress_mmr_sum.dml b/src/test/scripts/functions/compress/workload/WorkloadAnalysisL2SVM.dml
similarity index 70%
copy from src/test/scripts/functions/compress/compress_mmr_sum.dml
copy to src/test/scripts/functions/compress/workload/WorkloadAnalysisL2SVM.dml
index a3bedfb..1ea0528 100644
--- a/src/test/scripts/functions/compress/compress_mmr_sum.dml
+++ b/src/test/scripts/functions/compress/workload/WorkloadAnalysisL2SVM.dml
@@ -7,9 +7,9 @@
 # to you under the Apache License, Version 2.0 (the
 # "License"); you may not use this file except in compliance
 # with the License.  You may obtain a copy of the License at
-# 
+#
 #   http://www.apache.org/licenses/LICENSE-2.0
-# 
+#
 # Unless required by applicable law or agreed to in writing,
 # software distributed under the License is distributed on an
 # "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
@@ -19,8 +19,23 @@
 #
 #-------------------------------------------------------------
 
-x = read($A)
-v = rand(rows=ncol(x), cols=10, min=0.0, max=1.0, seed= 13);
-r = x %*% v  + 1
-s = sum(r)
-print(s)
+X = read($1);
+y = read($2);
+
+# Limit to one classification
+y = y == min(y)
+
+print("")
+print("LMCG")
+
+X = scale(X=X, scale=TRUE, center=TRUE);
+B = l2svm(X=X, Y=y, verbose=TRUE);
+[y_pred, n] = l2svmPredict(X=X, W=B, verbose=TRUE);
+
+classifications = (y_pred > 0.1)
+
+acc = sum(classifications == y)  / nrow(y)
+
+if(acc < 0.80)
+    stop("ERROR: to low accuracy achieved")
+print(acc)