svn commit: r703995 - in /incubator/hama/trunk: CHANGES.txt src/java/org/apache/hama/DenseMatrix.java

[edwardyoon]

Author: edwardyoon
Date: Mon Oct 13 03:00:46 2008
New Revision: 703995

URL: http://svn.apache.org/viewvc?rev=703995&view=rev
Log:
Add identity(int m, int n) which returns an m-by-n matrix with ones on the 
diagonal and zeros elsewhere.

Modified:
    incubator/hama/trunk/CHANGES.txt
    incubator/hama/trunk/src/java/org/apache/hama/DenseMatrix.java

Modified: incubator/hama/trunk/CHANGES.txt
URL: 
http://svn.apache.org/viewvc/incubator/hama/trunk/CHANGES.txt?rev=703995&r1=703994&r2=703995&view=diff
==============================================================================
--- incubator/hama/trunk/CHANGES.txt (original)
+++ incubator/hama/trunk/CHANGES.txt Mon Oct 13 03:00:46 2008
@@ -4,6 +4,7 @@
 
   NEW FEATURES
     
+    Hama-80: Add identity(int m, int n) which returns identity matrix 
(edwardyoon) 
     HAMA-62: Hama Shell Implementation (samuel via edwardyoon)
     HAMA-61: Load / save matrices from HTable (edwardyoon)
     HAMA-51: Add get/setRowAttribute() method (edwardyoon)

Modified: incubator/hama/trunk/src/java/org/apache/hama/DenseMatrix.java
URL: 
http://svn.apache.org/viewvc/incubator/hama/trunk/src/java/org/apache/hama/DenseMatrix.java?rev=703995&r1=703994&r2=703995&view=diff
==============================================================================
--- incubator/hama/trunk/src/java/org/apache/hama/DenseMatrix.java (original)
+++ incubator/hama/trunk/src/java/org/apache/hama/DenseMatrix.java Mon Oct 13 
03:00:46 2008
@@ -64,8 +64,8 @@
   public DenseMatrix(HamaConfiguration conf, String matrixName) {
     try {
       setConfiguration(conf);
-      this.matrixName = matrixName; 
-      if(store.matrixExists(matrixName)) {
+      this.matrixName = matrixName;
+      if (store.matrixExists(matrixName)) {
         this.matrixPath = store.getPath(matrixName);
       } else {
         this.matrixPath = matrixName;
@@ -138,6 +138,33 @@
     return rand;
   }
 
+  /**
+   * Generate identity matrix
+   * 
+   * @param conf configuration object
+   * @param m the number of rows.
+   * @param n the number of columns.
+   * @return an m-by-n matrix with ones on the diagonal and zeros elsewhere.
+   * @throws IOException
+   */
+  public static Matrix identity(HamaConfiguration conf, int m, int n)
+      throws IOException {
+    String name = RandomVariable.randMatrixName();
+    Matrix identity = new DenseMatrix(conf, name);
+
+    for (int i = 0; i < m; i++) {
+      DenseVector vector = new DenseVector();
+      for (int j = 0; j < n; j++) {
+        vector.set(j, (i == j ? 1.0 : 0.0));
+      }
+      identity.setRow(i, vector);
+    }
+
+    identity.setDimension(m, n);
+    LOG.info("Create the " + m + " * " + n + " identity matrix : " + name);
+    return identity;
+  }
+
   public Matrix add(Matrix B) throws IOException {
     String output = RandomVariable.randMatrixName();
     Matrix result = new DenseMatrix(config, output);