Author: luc
Date: Fri Jan 2 12:21:09 2009
New Revision: 730838
URL: http://svn.apache.org/viewvc?rev=730838&view=rev
Log:
added a static method createBlocksLayout to prepare array before constructing
the matrix
Modified:
commons/proper/math/trunk/src/java/org/apache/commons/math/linear/DenseRealMatrix.java
Modified:
commons/proper/math/trunk/src/java/org/apache/commons/math/linear/DenseRealMatrix.java
URL:
http://svn.apache.org/viewvc/commons/proper/math/trunk/src/java/org/apache/commons/math/linear/DenseRealMatrix.java?rev=730838&r1=730837&r2=730838&view=diff
==============================================================================
---
commons/proper/math/trunk/src/java/org/apache/commons/math/linear/DenseRealMatrix.java
(original)
+++
commons/proper/math/trunk/src/java/org/apache/commons/math/linear/DenseRealMatrix.java
Fri Jan 2 12:21:09 2009
@@ -104,14 +104,7 @@
blockColumns = (columns + BLOCK_SIZE - 1) / BLOCK_SIZE;
// allocate storage blocks, taking care of smaller ones at right and
bottom
- blocks = new double[blockRows * blockColumns][];
- int blockIndex = 0;
- for (int iBlock = 0; iBlock < blockRows; ++iBlock) {
- final int iHeight = blockHeight(iBlock);
- for (int jBlock = 0; jBlock < blockColumns; ++jBlock) {
- blocks[blockIndex++] = new double[iHeight *
blockWidth(jBlock)];
- }
- }
+ blocks = createBlocksLayout(rows, columns);
}
@@ -144,6 +137,7 @@
*
* @exception IllegalArgumentException if <code>blockData</code> shape is
* inconsistent with block layout
+ * @see #createBlocksLayout(int, int)
* @see #toBlocksLayout(double[][])
* @see #DenseRealMatrix(double[][])
*/
@@ -205,6 +199,7 @@
* @return a new data array containing the same entries but in blocks
layout
* @exception IllegalArgumentException if <code>rawData</code> is not
rectangular
* (not all rows have the same length)
+ * @see #createBlocksLayout(int, int)
* @see #DenseRealMatrix(int, int, double[][], boolean)
*/
public static double[][] toBlocksLayout(final double[][] rawData)
@@ -252,6 +247,41 @@
}
+ /**
+ * Create a data array in blocks layout.
+ * <p>
+ * This method can be used to create the array argument of the {...@link
+ * DenseRealMatrix#DenseRealMatrix(int, int, double[][], boolean)}
constructor.
+ * </p>
+ * @param rows the number of rows in the new matrix
+ * @param columns the number of columns in the new matrix
+ * @return a new data array in blocks layout
+ * @see #toBlocksLayout(double[][])
+ * @see #DenseRealMatrix(int, int, double[][], boolean)
+ */
+ public static double[][] createBlocksLayout(final int rows, final int
columns)
+ throws IllegalArgumentException {
+
+ final int blockRows = (rows + BLOCK_SIZE - 1) / BLOCK_SIZE;
+ final int blockColumns = (columns + BLOCK_SIZE - 1) / BLOCK_SIZE;
+
+ final double[][] blocks = new double[blockRows * blockColumns][];
+ for (int iBlock = 0, blockIndex = 0; iBlock < blockRows; ++iBlock) {
+ final int pStart = iBlock * BLOCK_SIZE;
+ final int pEnd = Math.min(pStart + BLOCK_SIZE, rows);
+ final int iHeight = pEnd - pStart;
+ for (int jBlock = 0; jBlock < blockColumns; ++jBlock,
++blockIndex) {
+ final int qStart = jBlock * BLOCK_SIZE;
+ final int qEnd = Math.min(qStart + BLOCK_SIZE, columns);
+ final int jWidth = qEnd - qStart;
+ blocks[blockIndex] = new double[iHeight * jWidth];
+ }
+ }
+
+ return blocks;
+
+ }
+
/** {...@inheritdoc} */
public RealMatrix createMatrix(final int rowDimension, final int
columnDimension)
throws IllegalArgumentException {
