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Posted to commits@commons.apache.org by eb...@apache.org on 2016/10/12 11:47:24 UTC
[math] MATH-1389: Performance improvement for
Array2DRowRealMatrix.getSubMatrix()
Repository: commons-math
Updated Branches:
refs/heads/master f672e826f -> 72df12fb2
MATH-1389: Performance improvement for Array2DRowRealMatrix.getSubMatrix()
Project: http://git-wip-us.apache.org/repos/asf/commons-math/repo
Commit: http://git-wip-us.apache.org/repos/asf/commons-math/commit/72df12fb
Tree: http://git-wip-us.apache.org/repos/asf/commons-math/tree/72df12fb
Diff: http://git-wip-us.apache.org/repos/asf/commons-math/diff/72df12fb
Branch: refs/heads/master
Commit: 72df12fb2ba453afb57cf185d25c502d4daec6d1
Parents: f672e82
Author: Christoph Dibak <ch...@ipvs.uni-stuttgart.de>
Authored: Wed Oct 12 12:41:45 2016 +0200
Committer: Emmanuel Bourg <eb...@apache.org>
Committed: Wed Oct 12 12:41:45 2016 +0200
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src/changes/changes.xml | 3 +++
.../math4/linear/Array2DRowRealMatrix.java | 18 ++++++++++++++++++
2 files changed, 21 insertions(+)
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http://git-wip-us.apache.org/repos/asf/commons-math/blob/72df12fb/src/changes/changes.xml
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diff --git a/src/changes/changes.xml b/src/changes/changes.xml
index 1e43272..ac6d23a 100644
--- a/src/changes/changes.xml
+++ b/src/changes/changes.xml
@@ -54,6 +54,9 @@ If the output is not quite correct, check for invisible trailing spaces!
</release>
<release version="4.0" date="XXXX-XX-XX" description="">
+ <action dev="ebourg" type="update" issue="MATH-1389" due-to="Christoph Dibak">
+ Performance improvement for Array2DRowRealMatrix.getSubMatrix()
+ </action>
<action dev="erans" type="add" issue="MATH-1383">
Dependency toward the "Commons Rng" component.
</action>
http://git-wip-us.apache.org/repos/asf/commons-math/blob/72df12fb/src/main/java/org/apache/commons/math4/linear/Array2DRowRealMatrix.java
----------------------------------------------------------------------
diff --git a/src/main/java/org/apache/commons/math4/linear/Array2DRowRealMatrix.java b/src/main/java/org/apache/commons/math4/linear/Array2DRowRealMatrix.java
index 3778db5..ed1ca9f 100644
--- a/src/main/java/org/apache/commons/math4/linear/Array2DRowRealMatrix.java
+++ b/src/main/java/org/apache/commons/math4/linear/Array2DRowRealMatrix.java
@@ -390,6 +390,24 @@ public class Array2DRowRealMatrix extends AbstractRealMatrix implements Serializ
/** {@inheritDoc} */
@Override
+ public RealMatrix getSubMatrix(final int startRow, final int endRow,
+ final int startColumn, final int endColumn)
+ throws OutOfRangeException, NumberIsTooSmallException {
+ MatrixUtils.checkSubMatrixIndex(this, startRow, endRow, startColumn, endColumn);
+ final int rowCount = endRow - startRow + 1;
+ final int columnCount = endColumn - startColumn + 1;
+ final double[][] outData = new double[rowCount][columnCount];
+ for (int i = 0; i < rowCount; ++i) {
+ System.arraycopy(data[startRow + i], startColumn, outData[i], 0, columnCount);
+ }
+
+ Array2DRowRealMatrix subMatrix = new Array2DRowRealMatrix();
+ subMatrix.data = outData;
+ return subMatrix;
+ }
+
+ /** {@inheritDoc} */
+ @Override
public double walkInRowOrder(final RealMatrixChangingVisitor visitor) {
final int rows = getRowDimension();
final int columns = getColumnDimension();