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 <[email protected]> Authored: Wed Oct 12 12:41:45 2016 +0200 Committer: Emmanuel Bourg <[email protected]> Committed: Wed Oct 12 12:41:45 2016 +0200 ---------------------------------------------------------------------- src/changes/changes.xml | 3 +++ .../math4/linear/Array2DRowRealMatrix.java | 18 ++++++++++++++++++ 2 files changed, 21 insertions(+) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/commons-math/blob/72df12fb/src/changes/changes.xml ---------------------------------------------------------------------- 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();
