From 204990415d62e4d0f6aa3818ccae3f0b7ad67b00 Mon Sep 17 00:00:00 2001
From: Luc Maisonobe <luc@apache.org>
Date: Wed, 16 Dec 2009 21:44:13 +0000
Subject: [PATCH] Fixed a wrong dimension check in SVD solver thanks to Dimitri
 for identifying and solving this

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@891436 13f79535-47bb-0310-9956-ffa450edef68
---
 .../math/linear/SingularValueDecomposition.java      |  4 ++--
 .../math/linear/SingularValueDecompositionImpl.java  | 12 ++++++------
 src/site/xdoc/changes.xml                            |  3 +++
 3 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/src/main/java/org/apache/commons/math/linear/SingularValueDecomposition.java b/src/main/java/org/apache/commons/math/linear/SingularValueDecomposition.java
index 38bac6c71..5f91636e6 100644
--- a/src/main/java/org/apache/commons/math/linear/SingularValueDecomposition.java
+++ b/src/main/java/org/apache/commons/math/linear/SingularValueDecomposition.java
@@ -24,8 +24,8 @@ package org.apache.commons.math.linear;
  * Singular Value Decomposition of a real matrix.
  * <p>The Singular Value Decomposition of matrix A is a set of three matrices:
  * U, &Sigma; and V such that A = U &times; &Sigma; &times; V<sup>T</sup>.
- * Let A be an m &times; n matrix, then U is an m &times; m orthogonal matrix,
- * &Sigma; is a m &times; n diagonal matrix with positive diagonal elements,
+ * Let A be an m &times; n matrix, then U is an m &times; n orthogonal matrix,
+ * &Sigma; is a n &times; n diagonal matrix with positive diagonal elements,
  * and V is an n &times; n orthogonal matrix.</p>
  * <p>This interface is similar to the class with similar name from the
  * <a href="http://math.nist.gov/javanumerics/jama/">JAMA</a> library, with the
diff --git a/src/main/java/org/apache/commons/math/linear/SingularValueDecompositionImpl.java b/src/main/java/org/apache/commons/math/linear/SingularValueDecompositionImpl.java
index a01cea377..0da87ab2a 100644
--- a/src/main/java/org/apache/commons/math/linear/SingularValueDecompositionImpl.java
+++ b/src/main/java/org/apache/commons/math/linear/SingularValueDecompositionImpl.java
@@ -24,8 +24,8 @@ import org.apache.commons.math.util.MathUtils;
  * Calculates the Singular Value Decomposition of a matrix.
  * <p>The Singular Value Decomposition of matrix A is a set of three matrices:
  * U, &Sigma; and V such that A = U &times; &Sigma; &times; V<sup>T</sup>.
- * Let A be an m &times; n matrix, then U is an m &times; m orthogonal matrix,
- * &Sigma; is a m &times; n diagonal matrix with positive diagonal elements,
+ * Let A be an m &times; n matrix, then U is an m &times; n orthogonal matrix,
+ * &Sigma; is a n &times; n diagonal matrix with positive diagonal elements,
  * and V is an n &times; n orthogonal matrix.</p>
  *
  * @version $Revision$ $Date$
@@ -361,10 +361,10 @@ public class SingularValueDecompositionImpl implements SingularValueDecompositio
         public double[] solve(final double[] b)
             throws IllegalArgumentException, InvalidMatrixException {
 
-            if (b.length != singularValues.length) {
+            if (b.length != uT.getColumnDimension()) {
                 throw MathRuntimeException.createIllegalArgumentException(
                         "vector length mismatch: got {0} but expected {1}",
-                        b.length, singularValues.length);
+                        b.length, uT.getColumnDimension());
             }
 
             final double[] w = uT.operate(b);
@@ -390,10 +390,10 @@ public class SingularValueDecompositionImpl implements SingularValueDecompositio
         public RealVector solve(final RealVector b)
             throws IllegalArgumentException, InvalidMatrixException {
 
-            if (b.getDimension() != singularValues.length) {
+            if (b.getDimension() != uT.getColumnDimension()) {
                 throw MathRuntimeException.createIllegalArgumentException(
                         "vector length mismatch: got {0} but expected {1}",
-                         b.getDimension(), singularValues.length);
+                         b.getDimension(), uT.getColumnDimension());
             }
 
             final RealVector w = uT.operate(b);
diff --git a/src/site/xdoc/changes.xml b/src/site/xdoc/changes.xml
index 70c612e31..a72e7c193 100644
--- a/src/site/xdoc/changes.xml
+++ b/src/site/xdoc/changes.xml
@@ -39,6 +39,9 @@ The <action> type attribute can be add,update,fix,remove.
   </properties>
   <body>
     <release version="2.1" date="TBD" description="TBD">
+      <action dev="luc" type="fix" due-to="Dimitri Pourbaix">
+        Fixed a wrong dimension check in SVD solver.
+      </action>
       <action dev="luc" type="fix" issue="MATH-313" due-to="Jake Mannix">
         Added composition features for real functions.
       </action>