Import Upstream version 0.6.0~beta2

1 files changed, 28 insertions, 40 deletions

diff --git a/src/de/lmu/ifi/dbs/elki/distance/distancefunction/CanberraDistanceFunction.java b/src/de/lmu/ifi/dbs/elki/distance/distancefunction/CanberraDistanceFunction.java
index f6db7439..97ef19ce 100644
--- a/src/de/lmu/ifi/dbs/elki/distance/distancefunction/CanberraDistanceFunction.java
+++ b/src/de/lmu/ifi/dbs/elki/distance/distancefunction/CanberraDistanceFunction.java
@@ -24,10 +24,7 @@ package de.lmu.ifi.dbs.elki.distance.distancefunction;
  */
 import de.lmu.ifi.dbs.elki.data.NumberVector;
 import de.lmu.ifi.dbs.elki.data.spatial.SpatialComparable;
-import de.lmu.ifi.dbs.elki.database.query.distance.SpatialDistanceQuery;
-import de.lmu.ifi.dbs.elki.database.query.distance.SpatialPrimitiveDistanceQuery;
-import de.lmu.ifi.dbs.elki.database.relation.Relation;
-import de.lmu.ifi.dbs.elki.distance.distancevalue.DoubleDistance;
+import de.lmu.ifi.dbs.elki.utilities.Alias;
 import de.lmu.ifi.dbs.elki.utilities.documentation.Reference;
 import de.lmu.ifi.dbs.elki.utilities.optionhandling.AbstractParameterizer;
 
@@ -45,7 +42,8 @@ import de.lmu.ifi.dbs.elki.utilities.optionhandling.AbstractParameterizer;
  * @author Erich Schubert
  */
 @Reference(authors = "G. N. Lance, W. T. Williams", title = "Computer programs for hierarchical polythetic classification (similarity analysis).", booktitle = "Computer Journal, Volume 9, Issue 1", url = "http://comjnl.oxfordjournals.org/content/9/1/60.short")
-public class CanberraDistanceFunction extends AbstractVectorDoubleDistanceFunction implements SpatialPrimitiveDoubleDistanceFunction<NumberVector<?>> {
+@Alias({ "canberra" })
+public class CanberraDistanceFunction extends AbstractSpatialDoubleDistanceFunction {
   /**
    * Static instance. Use this!
    */
@@ -59,56 +57,46 @@ public class CanberraDistanceFunction extends AbstractVectorDoubleDistanceFuncti
   }
 
   @Override
-  public double doubleDistance(NumberVector<?> o1, NumberVector<?> o2) {
-    final int dim = o1.getDimensionality();
-    double sum = 0.0;
-    for(int i = 0; i < dim; i++) {
-      double v1 = o1.doubleValue(i);
-      double v2 = o2.doubleValue(i);
-      final double div = Math.abs(v1) + Math.abs(v2);
+  public double doubleDistance(NumberVector<?> v1, NumberVector<?> v2) {
+    final int dim = dimensionality(v1, v2);
+    double agg = 0.;
+    for (int d = 0; d < dim; d++) {
+      final double xd = v1.doubleValue(d), yd = v2.doubleValue(d);
+      final double div = Math.abs(xd) + Math.abs(yd);
       if (div > 0) {
-        sum += Math.abs(v1 - v2) / div;
+        agg += Math.abs(xd - yd) / div;
       }
     }
-    return sum;
+    return agg;
   }
 
   @Override
   public double doubleMinDist(SpatialComparable mbr1, SpatialComparable mbr2) {
-    final int dim = mbr1.getDimensionality();
-    double sum = 0.0;
-    for(int d = 0; d < dim; d++) {
-      final double m1, m2;
-      if(mbr1.getMax(d) < mbr2.getMin(d)) {
-        m1 = mbr2.getMin(d);
-        m2 = mbr1.getMax(d);
-      }
-      else if(mbr1.getMin(d) > mbr2.getMax(d)) {
-        m1 = mbr1.getMin(d);
-        m2 = mbr2.getMax(d);
-      }
-      else { // The mbrs intersect!
+    final int dim = dimensionality(mbr1, mbr2);
+    double agg = 0.;
+    for (int d = 0; d < dim; d++) {
+      final double diff;
+      if (mbr1.getMax(d) < mbr2.getMin(d)) {
+        diff = mbr2.getMin(d) - mbr1.getMax(d);
+      } else if (mbr1.getMin(d) > mbr2.getMax(d)) {
+        diff = mbr1.getMin(d) - mbr2.getMax(d);
+      } else { // The mbrs intersect!
         continue;
       }
-      final double manhattanI = m1 - m2;
       final double a1 = Math.max(-mbr1.getMin(d), mbr1.getMax(d));
       final double a2 = Math.max(-mbr2.getMin(d), mbr2.getMax(d));
       final double div = a1 + a2;
-      if (div > 0) {
-        sum += manhattanI / div;
-      }
+      // Cannot be 0, because then diff = 0 and we continued above.
+      agg += diff / div;
     }
-    return sum;
-  }
-
-  @Override
-  public DoubleDistance minDist(SpatialComparable mbr1, SpatialComparable mbr2) {
-    return new DoubleDistance(doubleMinDist(mbr1, mbr2));
+    return agg;
   }
 
   @Override
-  public <T extends NumberVector<?>> SpatialDistanceQuery<T, DoubleDistance> instantiate(Relation<T> relation) {
-    return new SpatialPrimitiveDistanceQuery<T, DoubleDistance>(relation, this);
+  public boolean isMetric() {
+    // As this is also reffered to as "canberra metric", it is probably a metric
+    // But *maybe* only for positive numbers only?
+    return true;
   }
 
   /**
@@ -124,4 +112,4 @@ public class CanberraDistanceFunction extends AbstractVectorDoubleDistanceFuncti
       return CanberraDistanceFunction.STATIC;
     }
   }
-}
\ No newline at end of file
+}