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Posted to commits@commons.apache.org by er...@apache.org on 2019/10/28 01:46:06 UTC
[commons-math] 07/08: Code upgraded following MATH-1500.
This is an automated email from the ASF dual-hosted git repository.
erans pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/commons-math.git
commit 9988a5b3c4779eadfad9ea0c4925f5b327317814
Author: Gilles Sadowski <gi...@harfang.homelinux.org>
AuthorDate: Sun Oct 27 15:11:56 2019 +0100
Code upgraded following MATH-1500.
---
.../ode/nonstiff/AdamsNordsieckTransformer.java | 72 ++++++++++++----------
1 file changed, 40 insertions(+), 32 deletions(-)
diff --git a/src/main/java/org/apache/commons/math4/ode/nonstiff/AdamsNordsieckTransformer.java b/src/main/java/org/apache/commons/math4/ode/nonstiff/AdamsNordsieckTransformer.java
index 7cf5a4e..60f5ee7 100644
--- a/src/main/java/org/apache/commons/math4/ode/nonstiff/AdamsNordsieckTransformer.java
+++ b/src/main/java/org/apache/commons/math4/ode/nonstiff/AdamsNordsieckTransformer.java
@@ -21,16 +21,17 @@ import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
-import org.apache.commons.math4.fraction.BigFraction;
+import org.apache.commons.numbers.fraction.BigFraction;
+import org.apache.commons.numbers.field.BigFractionField;
import org.apache.commons.math4.linear.Array2DRowFieldMatrix;
import org.apache.commons.math4.linear.Array2DRowRealMatrix;
import org.apache.commons.math4.linear.ArrayFieldVector;
-import org.apache.commons.math4.linear.FieldDecompositionSolver;
-import org.apache.commons.math4.linear.FieldLUDecomposition;
-import org.apache.commons.math4.linear.FieldMatrix;
import org.apache.commons.math4.linear.MatrixUtils;
import org.apache.commons.math4.linear.QRDecomposition;
import org.apache.commons.math4.linear.RealMatrix;
+import org.apache.commons.math4.field.linalg.FieldDenseMatrix;
+import org.apache.commons.math4.field.linalg.FieldDecompositionSolver;
+import org.apache.commons.math4.field.linalg.FieldLUDecomposition;
/** Transformer to Nordsieck vectors for Adams integrators.
* <p>This class is used by {@link AdamsBashforthIntegrator Adams-Bashforth} and
@@ -148,38 +149,45 @@ public class AdamsNordsieckTransformer {
* (excluding the one being computed)
*/
private AdamsNordsieckTransformer(final int n) {
-
- final int rows = n - 1;
+ final int dim = n - 1;
// compute exact coefficients
- FieldMatrix<BigFraction> bigP = buildP(rows);
- FieldDecompositionSolver<BigFraction> pSolver =
- new FieldLUDecomposition<>(bigP).getSolver();
+ final FieldDenseMatrix<BigFraction> bigP = buildP(dim);
+ final FieldDecompositionSolver<BigFraction> pSolver = FieldLUDecomposition.of(bigP).getSolver();
- BigFraction[] u = new BigFraction[rows];
- Arrays.fill(u, BigFraction.ONE);
- BigFraction[] bigC1 = pSolver.solve(new ArrayFieldVector<>(u, false)).toArray();
+ final FieldDenseMatrix<BigFraction> u = FieldDenseMatrix.create(BigFractionField.get(), dim, 1)
+ .fill(BigFraction.ONE);
+ final FieldDenseMatrix<BigFraction> bigC1 = pSolver.solve(u);
// update coefficients are computed by combining transform from
// Nordsieck to multistep, then shifting rows to represent step advance
// then applying inverse transform
- BigFraction[][] shiftedP = bigP.getData();
- for (int i = shiftedP.length - 1; i > 0; --i) {
+ final FieldDenseMatrix<BigFraction> shiftedP = bigP.copy();
+ for (int i = dim - 1; i > 0; --i) {
// shift rows
- shiftedP[i] = shiftedP[i - 1];
+ for (int j = 0; j < dim; j++) {
+ shiftedP.set(i, j, shiftedP.get(i - 1, j));
+ }
}
- shiftedP[0] = new BigFraction[rows];
- Arrays.fill(shiftedP[0], BigFraction.ZERO);
- FieldMatrix<BigFraction> bigMSupdate =
- pSolver.solve(new Array2DRowFieldMatrix<>(shiftedP, false));
+ for (int j = 0; j < dim; j++) {
+ shiftedP.set(0, j, BigFraction.ZERO);
+ }
+
+ final FieldDenseMatrix<BigFraction> bigMSupdate = pSolver.solve(shiftedP);
// convert coefficients to double
- update = MatrixUtils.bigFractionMatrixToRealMatrix(bigMSupdate);
- c1 = new double[rows];
- for (int i = 0; i < rows; ++i) {
- c1[i] = bigC1[i].doubleValue();
+ final double[][] updateData = new double[dim][dim];
+ for (int i = 0; i < dim; i++) {
+ for (int j = 0; j < dim; j++) {
+ updateData[i][j] = bigMSupdate.get(i, j).doubleValue();
+ }
}
+ update = new Array2DRowRealMatrix(updateData, false);
+ c1 = new double[dim];
+ for (int i = 0; i < dim; ++i) {
+ c1[i] = bigC1.get(i, 0).doubleValue();
+ }
}
/** Get the Nordsieck transformer for a given number of steps.
@@ -223,23 +231,23 @@ public class AdamsNordsieckTransformer {
* @param rows number of rows of the matrix
* @return P matrix
*/
- private FieldMatrix<BigFraction> buildP(final int rows) {
+ private FieldDenseMatrix<BigFraction> buildP(final int rows) {
+ final FieldDenseMatrix<BigFraction> pData = FieldDenseMatrix.create(BigFractionField.get(),
+ rows, rows)
+ .fill(BigFraction.ZERO);
- final BigFraction[][] pData = new BigFraction[rows][rows];
-
- for (int i = 1; i <= pData.length; ++i) {
+ for (int i = 1; i <= rows; ++i) {
// build the P matrix elements from Taylor series formulas
- final BigFraction[] pI = pData[i - 1];
final int factor = -i;
int aj = factor;
- for (int j = 1; j <= pI.length; ++j) {
- pI[j - 1] = new BigFraction(aj * (j + 1));
+ for (int j = 1; j <= rows; ++j) {
+ pData.set(i - 1, j - 1,
+ BigFraction.of(aj * (j + 1)));
aj *= factor;
}
}
- return new Array2DRowFieldMatrix<>(pData, false);
-
+ return pData;
}
/** Initialize the high order scaled derivatives at step start.