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Fixed an overflow error in MathUtils.distance that was causing KMeansPlusPlusClusterer to fail with a NullPointerException when 

component distances between points exceeded Integer.MAXVALUE.
JIRA: MATH-305
Reported by Erik van Ingen

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@885027 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Phil Steitz 2009-11-27 21:45:38 +00:00
parent 9e6576e7cd
commit ef9b639afc
3 changed files with 29 additions and 2 deletions
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4
src/main/java/org/apache/commons/math/util/MathUtils.java
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@ -1621,9 +1621,9 @@ public final class MathUtils {
* @return the L<sub>2</sub> distance between the two points * @return the L<sub>2</sub> distance between the two points
*/ */
public static double distance(int[] p1, int[] p2) { public static double distance(int[] p1, int[] p2) {
int sum = 0; double sum = 0;
for (int i = 0; i < p1.length; i++) { for (int i = 0; i < p1.length; i++) {
final int dp = p1[i] - p2[i]; final double dp = p1[i] - p2[i];
sum += dp * dp; sum += dp * dp;
} }
return Math.sqrt(sum); return Math.sqrt(sum);

5
src/site/xdoc/changes.xml
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@ -39,6 +39,11 @@ The <action> type attribute can be add,update,fix,remove.
</properties> </properties>
<body> <body>
<release version="2.1" date="TBD" description="TBD"> <release version="2.1" date="TBD" description="TBD">
<action dev="psteitz" type="fix" issue="MATH-305" due-to="Erik van Ingen">
Fixed an overflow error in MathUtils.distance that was causing KMeansPlusPlusClusterer
to fail with a NullPointerException when component distances between points
exceeded Integer.MAXVALUE.
</action>
<action dev="psteitz" type="update" issue="MATH-315" due-to="Mikkel Meyer Andersen"> <action dev="psteitz" type="update" issue="MATH-315" due-to="Mikkel Meyer Andersen">
Added generationsEvolved property to GeneticAlgorithm to track the number of generations Added generationsEvolved property to GeneticAlgorithm to track the number of generations
evolved by the evolve() method before reaching the StoppingCondition. evolved by the evolve() method before reaching the StoppingCondition.

22
src/test/java/org/apache/commons/math/stat/clustering/KMeansPlusPlusClustererTest.java
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@ -94,4 +94,26 @@ public class KMeansPlusPlusClustererTest {
} }
/**
* JIRA: MATH-305
*
* Two points, one cluster, one iteration
*/
@Test
public void testPerformClusterAnalysisDegenerate() {
KMeansPlusPlusClusterer<EuclideanIntegerPoint> transformer = new KMeansPlusPlusClusterer<EuclideanIntegerPoint>(
new Random(1746432956321l));
EuclideanIntegerPoint[] points = new EuclideanIntegerPoint[] {
new EuclideanIntegerPoint(new int[] { 1959, 325100 }),
new EuclideanIntegerPoint(new int[] { 1960, 373200 }), };
List<Cluster<EuclideanIntegerPoint>> clusters = transformer.cluster(Arrays.asList(points), 1, 1);
assertEquals(1, clusters.size());
assertEquals(2, (clusters.get(0).getPoints().size()));
EuclideanIntegerPoint pt1 = new EuclideanIntegerPoint(new int[] { 1959, 325100 });
EuclideanIntegerPoint pt2 = new EuclideanIntegerPoint(new int[] { 1960, 373200 });
assertTrue(clusters.get(0).getPoints().contains(pt1));
assertTrue(clusters.get(0).getPoints().contains(pt2));
}
} }