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From Mikkel Meyer Andersen <m...@mikl.dk>
Subject Re: svn commit: r904231 - in /commons/proper/math/trunk/src: main/java/org/apache/commons/math/linear/AbstractRealVector.java site/xdoc/changes.xml test/java/org/apache/commons/math/linear/ArrayRealVectorTest.java
Date Thu, 28 Jan 2010 20:05:44 GMT
Hi.

Thanks!

Why use an iterator instead of just a simple for-loop? And what about saving
the values until the vector invalidates - I see pros and cons for both
approaches, so it's more to hear what your thoughts were?

Cheers, Mikkel.

On 28/01/2010 8:42 PM, <luc@apache.org> wrote:

Author: luc
Date: Thu Jan 28 19:42:31 2010
New Revision: 904231

URL: http://svn.apache.org/viewvc?rev=904231&view=rev
Log:
added min/max getters for real vectors
For compatibility reasons, these methods have been put in the topmost
abstract class but not in the interface yet. It could be pushed to the
interface when next major version will be released.
JIRA: MATH-334

Modified:

 commons/proper/math/trunk/src/main/java/org/apache/commons/math/linear/AbstractRealVector.java
   commons/proper/math/trunk/src/site/xdoc/changes.xml

 commons/proper/math/trunk/src/test/java/org/apache/commons/math/linear/ArrayRealVectorTest.java

Modified:
commons/proper/math/trunk/src/main/java/org/apache/commons/math/linear/AbstractRealVector.java
URL:
http://svn.apache.org/viewvc/commons/proper/math/trunk/src/main/java/org/apache/commons/math/linear/AbstractRealVector.java?rev=904231&r1=904230&r2=904231&view=diff
==============================================================================
---
commons/proper/math/trunk/src/main/java/org/apache/commons/math/linear/AbstractRealVector.java
(original)
+++
commons/proper/math/trunk/src/main/java/org/apache/commons/math/linear/AbstractRealVector.java
Thu Jan 28 19:42:31 2010
@@ -292,6 +292,58 @@
        return d;
    }

+    /** Get the index of the minimum entry.
+     * @return index of the minimum entry or -1 if vector length is 0
+     * or all entries are NaN
+     */
+    public int getMinIndex() {
+        int minIndex    = -1;
+        double minValue = Double.POSITIVE_INFINITY;
+        Iterator<Entry> iterator = iterator();
+        while (iterator.hasNext()) {
+            final Entry entry = iterator.next();
+            if (entry.getValue() <= minValue) {
+                minIndex = entry.getIndex();
+                minValue = entry.getValue();
+            }
+        }
+        return minIndex;
+    }
+
+    /** Get the value of the minimum entry.
+     * @return value of the minimum entry or NaN if all entries are NaN
+     */
+    public double getMinValue() {
+        final int minIndex = getMinIndex();
+        return minIndex < 0 ? Double.NaN : getEntry(minIndex);
+    }
+
+    /** Get the index of the maximum entry.
+     * @return index of the maximum entry or -1 if vector length is 0
+     * or all entries are NaN
+     */
+    public int getMaxIndex() {
+        int maxIndex    = -1;
+        double maxValue = Double.NEGATIVE_INFINITY;
+        Iterator<Entry> iterator = iterator();
+        while (iterator.hasNext()) {
+            final Entry entry = iterator.next();
+            if (entry.getValue() >= maxValue) {
+                maxIndex = entry.getIndex();
+                maxValue = entry.getValue();
+            }
+        }
+        return maxIndex;
+    }
+
+    /** Get the value of the maximum entry.
+     * @return value of the maximum entry or NaN if all entries are NaN
+     */
+    public double getMaxValue() {
+        final int maxIndex = getMaxIndex();
+        return maxIndex < 0 ? Double.NaN : getEntry(maxIndex);
+    }
+
    /** {@inheritDoc} */
    public RealVector mapAbs() {
        return copy().mapAbsToSelf();

Modified: commons/proper/math/trunk/src/site/xdoc/changes.xml
URL:
http://svn.apache.org/viewvc/commons/proper/math/trunk/src/site/xdoc/changes.xml?rev=904231&r1=904230&r2=904231&view=diff
==============================================================================
--- commons/proper/math/trunk/src/site/xdoc/changes.xml (original)
+++ commons/proper/math/trunk/src/site/xdoc/changes.xml Thu Jan 28 19:42:31
2010
@@ -39,6 +39,10 @@
  </properties>
  <body>
    <release version="2.1" date="TBD" description="TBD">
+      <action dev="luc" type="add" issue="MATH-334" >
+        Added min/max getters for real vectors (not yet in the RealVector
interface for
+        compatibility purposes, but in the AbstractRealVector abstract
class).
+      </action>
      <action dev="luc" type="fix" issue="MATH-338" due-to="Vincent Morand">
        Fixed automatic step initialization in embedded Runge-Kutta
integrators.
        The relative tolerance setting was never used, only the absolute
tolerance

Modified:
commons/proper/math/trunk/src/test/java/org/apache/commons/math/linear/ArrayRealVectorTest.java
URL:
http://svn.apache.org/viewvc/commons/proper/math/trunk/src/test/java/org/apache/commons/math/linear/ArrayRealVectorTest.java?rev=904231&r1=904230&r2=904231&view=diff
==============================================================================
---
commons/proper/math/trunk/src/test/java/org/apache/commons/math/linear/ArrayRealVectorTest.java
(original)
+++
commons/proper/math/trunk/src/test/java/org/apache/commons/math/linear/ArrayRealVectorTest.java
Thu Jan 28 19:42:31 2010
@@ -1308,6 +1308,30 @@
    }


+    public void testMinMax()  {
+        ArrayRealVector v1 = new ArrayRealVector(new double[] { 0, -6, 4,
12, 7 });
+        assertEquals(1,  v1.getMinIndex());
+        assertEquals(-6, v1.getMinValue(), 1.0e-12);
+        assertEquals(3,  v1.getMaxIndex());
+        assertEquals(12, v1.getMaxValue(), 1.0e-12);
+        ArrayRealVector v2 = new ArrayRealVector(new double[] { Double.NaN,
3, Double.NaN, -2 });
+        assertEquals(3,  v2.getMinIndex());
+        assertEquals(-2, v2.getMinValue(), 1.0e-12);
+        assertEquals(1,  v2.getMaxIndex());
+        assertEquals(3, v2.getMaxValue(), 1.0e-12);
+        ArrayRealVector v3 = new ArrayRealVector(new double[] { Double.NaN,
Double.NaN });
+        assertEquals(-1,  v3.getMinIndex());
+        assertTrue(Double.isNaN(v3.getMinValue()));
+        assertEquals(-1,  v3.getMaxIndex());
+        assertTrue(Double.isNaN(v3.getMaxValue()));
+        ArrayRealVector v4 = new ArrayRealVector(new double[0]);
+        assertEquals(-1,  v4.getMinIndex());
+        assertTrue(Double.isNaN(v4.getMinValue()));
+        assertEquals(-1,  v4.getMaxIndex());
+        assertTrue(Double.isNaN(v4.getMaxValue()));
+    }
+
+
    /** verifies that two vectors are close (sup norm) */
    protected void assertClose(String msg, double[] m, double[] n,
            double tolerance) {

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