Author: robinanil
Date: Mon Feb 22 14:38:48 2010
New Revision: 912585
URL: http://svn.apache.org/viewvc?rev=912585&view=rev
Log:
Distance Measure improvements
Modified:
lucene/mahout/trunk/core/src/main/java/org/apache/mahout/common/distance/CosineDistanceMeasure.java
lucene/mahout/trunk/core/src/main/java/org/apache/mahout/common/distance/ManhattanDistanceMeasure.java
lucene/mahout/trunk/core/src/main/java/org/apache/mahout/common/distance/SquaredEuclideanDistanceMeasure.java
lucene/mahout/trunk/core/src/main/java/org/apache/mahout/common/distance/TanimotoDistanceMeasure.java
Modified:
lucene/mahout/trunk/core/src/main/java/org/apache/mahout/common/distance/CosineDistanceMeasure.java
URL:
http://svn.apache.org/viewvc/lucene/mahout/trunk/core/src/main/java/org/apache/mahout/common/distance/CosineDistanceMeasure.java?rev=912585&r1=912584&r2=912585&view=diff
==============================================================================
---
lucene/mahout/trunk/core/src/main/java/org/apache/mahout/common/distance/CosineDistanceMeasure.java
(original)
+++
lucene/mahout/trunk/core/src/main/java/org/apache/mahout/common/distance/CosineDistanceMeasure.java
Mon Feb 22 14:38:48 2010
@@ -19,7 +19,6 @@
import java.util.Collection;
import java.util.Collections;
-import java.util.Iterator;
import org.apache.hadoop.mapred.JobConf;
import org.apache.mahout.common.parameters.Parameter;
@@ -71,18 +70,8 @@
if (v1.size() != v2.size()) {
throw new CardinalityException();
}
- double lengthSquaredv1 = 0.0;
- Iterator<Vector.Element> iter = v1.iterateNonZero();
- while (iter.hasNext()) {
- Vector.Element elt = iter.next();
- lengthSquaredv1 += elt.get() * elt.get();
- }
- iter = v2.iterateNonZero();
- double lengthSquaredv2 = 0.0;
- while (iter.hasNext()) {
- Vector.Element elt = iter.next();
- lengthSquaredv2 += elt.get() * elt.get();
- }
+ double lengthSquaredv1 = v1.getLengthSquared();
+ double lengthSquaredv2 = v2.getLengthSquared();
double dotProduct = v1.dot(v2);
double denominator = Math.sqrt(lengthSquaredv1) *
Math.sqrt(lengthSquaredv2);
@@ -97,12 +86,8 @@
@Override
public double distance(double centroidLengthSquare, Vector centroid, Vector
v) {
- Iterator<Vector.Element> iter = v.iterateNonZero();
- double lengthSquaredv = 0.0;
- while (iter.hasNext()) {
- Vector.Element elt = iter.next();
- lengthSquaredv += elt.get() * elt.get();
- }
+
+ double lengthSquaredv = v.getLengthSquared();
double dotProduct = centroid.dot(v);
double denominator = Math.sqrt(centroidLengthSquare) *
Math.sqrt(lengthSquaredv);
Modified:
lucene/mahout/trunk/core/src/main/java/org/apache/mahout/common/distance/ManhattanDistanceMeasure.java
URL:
http://svn.apache.org/viewvc/lucene/mahout/trunk/core/src/main/java/org/apache/mahout/common/distance/ManhattanDistanceMeasure.java?rev=912585&r1=912584&r2=912585&view=diff
==============================================================================
---
lucene/mahout/trunk/core/src/main/java/org/apache/mahout/common/distance/ManhattanDistanceMeasure.java
(original)
+++
lucene/mahout/trunk/core/src/main/java/org/apache/mahout/common/distance/ManhattanDistanceMeasure.java
Mon Feb 22 14:38:48 2010
@@ -62,9 +62,8 @@
}
double result = 0;
Vector vector = v1.minus(v2);
- Iterator<Vector.Element> iter = vector.iterateNonZero(); // this contains
all non zero elements between
- // the
- // two
+ Iterator<Vector.Element> iter = vector.iterateNonZero();
+ // this contains all non zero elements between the two
while (iter.hasNext()) {
Vector.Element e = iter.next();
result += Math.abs(e.get());
Modified:
lucene/mahout/trunk/core/src/main/java/org/apache/mahout/common/distance/SquaredEuclideanDistanceMeasure.java
URL:
http://svn.apache.org/viewvc/lucene/mahout/trunk/core/src/main/java/org/apache/mahout/common/distance/SquaredEuclideanDistanceMeasure.java?rev=912585&r1=912584&r2=912585&view=diff
==============================================================================
---
lucene/mahout/trunk/core/src/main/java/org/apache/mahout/common/distance/SquaredEuclideanDistanceMeasure.java
(original)
+++
lucene/mahout/trunk/core/src/main/java/org/apache/mahout/common/distance/SquaredEuclideanDistanceMeasure.java
Mon Feb 22 14:38:48 2010
@@ -49,7 +49,7 @@
@Override
public double distance(Vector v1, Vector v2) {
- return v1.getDistanceSquared(v2);
+ return v2.getDistanceSquared(v1);
}
@Override
Modified:
lucene/mahout/trunk/core/src/main/java/org/apache/mahout/common/distance/TanimotoDistanceMeasure.java
URL:
http://svn.apache.org/viewvc/lucene/mahout/trunk/core/src/main/java/org/apache/mahout/common/distance/TanimotoDistanceMeasure.java?rev=912585&r1=912584&r2=912585&view=diff
==============================================================================
---
lucene/mahout/trunk/core/src/main/java/org/apache/mahout/common/distance/TanimotoDistanceMeasure.java
(original)
+++
lucene/mahout/trunk/core/src/main/java/org/apache/mahout/common/distance/TanimotoDistanceMeasure.java
Mon Feb 22 14:38:48 2010
@@ -39,8 +39,16 @@
*/
@Override
public double distance(Vector a, Vector b) {
- double ab = dot(a, b);
- double denominator = dot(a, a) + dot(b, b) - ab;
+ double ab = 0;
+ double denominator = 0;
+ if (getWeights() != null) {
+ ab = dot(b, a); // b is SequentialAccess
+ denominator = dot(a, a) + dot(b, b) - ab;
+ } else {
+ ab = b.dot(a); // b is SequentialAccess
+ denominator = a.getLengthSquared() + b.getLengthSquared() - ab;
+ }
+
if (denominator < ab) { // correct for fp round-off: distance >= 0
denominator = ab;
}
@@ -61,9 +69,7 @@
while (it.hasNext() && (el = it.next()) != null) {
double elementValue = el.get();
double value = elementValue * (sameVector ? elementValue :
b.getQuick(el.index()));
- if (weights != null) {
- value *= weights.getQuick(el.index());
- }
+ value *= weights.getQuick(el.index());
dot += value;
}
return dot;
