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https://issues.apache.org/jira/browse/MAHOUT-66?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12611742#action_12611742
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Karl Wettin commented on MAHOUT-66:
-----------------------------------
What is it that actually does not work when using SparseVector? I just added
this to the trunk test and it passes for all distance measure classes:
{code}
Index:
core/src/test/java/org/apache/mahout/utils/DefaultDistanceMeasureTest.java
===================================================================
--- core/src/test/java/org/apache/mahout/utils/DefaultDistanceMeasureTest.java
(revision 674908)
+++ core/src/test/java/org/apache/mahout/utils/DefaultDistanceMeasureTest.java
(working copy)
@@ -20,6 +20,7 @@
import junit.framework.TestCase;
import org.apache.mahout.matrix.DenseVector;
import org.apache.mahout.matrix.Vector;
+import org.apache.mahout.matrix.SparseVector;
public abstract class DefaultDistanceMeasureTest extends TestCase {
@@ -59,4 +60,51 @@
}
+ public void testMeasureSparse() throws Exception {
+
+ DistanceMeasure distanceMeasure = distanceMeasureFactory();
+
+ Vector[] vectors = new Vector[]{
+ new SparseVector(6),
+ new SparseVector(6),
+ new SparseVector(6)
+ };
+
+ for (int i=0; i<6; i++) {
+ vectors[0].set(i, 1);
+ }
+
+ for (int i=0; i<6; i++) {
+ vectors[1].set(i, 2);
+ }
+ for (int i=0; i<6; i++) {
+ vectors[2].set(i, 6);
+ }
+
+
+
+
+ double[][] distanceMatrix = new double[3][3];
+
+ for (int a = 0; a < 3; a++) {
+ for (int b = 0; b < 3; b++) {
+ distanceMatrix[a][b] = distanceMeasure.distance(vectors[a],
vectors[b]);
+ }
+ }
+
+ assertEquals(0d, distanceMatrix[0][0]);
+ assertTrue(distanceMatrix[0][0] < distanceMatrix[0][1]);
+ assertTrue(distanceMatrix[0][1] < distanceMatrix[0][2]);
+
+ assertEquals(0d, distanceMatrix[1][1]);
+ assertTrue(distanceMatrix[1][0] > distanceMatrix[1][1]);
+ assertTrue(distanceMatrix[1][2] > distanceMatrix[1][0]);
+
+ assertEquals(0d, distanceMatrix[2][2]);
+ assertTrue(distanceMatrix[2][0] > distanceMatrix[2][1]);
+ assertTrue(distanceMatrix[2][1] > distanceMatrix[2][2]);
+
+
+ }
+
}
{code}
> EuclideanDistanceMeasure and ManhattanDistanceMeasure classes does not
> compute distance for Sparse Vectors
> ----------------------------------------------------------------------------------------------------------
>
> Key: MAHOUT-66
> URL: https://issues.apache.org/jira/browse/MAHOUT-66
> Project: Mahout
> Issue Type: Bug
> Components: Clustering
> Reporter: Pallavi Palleti
> Priority: Minor
> Attachments: MAHOUT-66.patch, MAHOUT-66.patch
>
>
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