/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.mahout.clustering.meanshift;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import org.apache.mahout.clustering.kmeans.Kluster;
import org.apache.mahout.common.distance.DistanceMeasure;
import org.apache.mahout.math.Vector;
import org.apache.mahout.math.VectorWritable;
import org.apache.mahout.math.list.IntArrayList;
/**
* This class models a canopy as a center point, the number of points that are
* contained within it according to the application of some distance metric, and
* a point total which is the sum of all the points and is used to compute the
* centroid when needed.
*/
@Deprecated
public class MeanShiftCanopy extends Kluster {
// TODO: this is still problematic from a scalability perspective, but how
// else to encode membership?
private IntArrayList boundPoints = new IntArrayList();
private int mass = 0;
public int getMass() {
return mass;
}
void setMass(int num) {
mass = num;
}
/**
* Used for Writable
*/
public MeanShiftCanopy() {
}
/**
* Create a new Canopy containing the given point
*
* @param point
* a Vector
* @param id
* an int canopy id
* @param measure
* a DistanceMeasure
*/
public MeanShiftCanopy(Vector point, int id, DistanceMeasure measure) {
super(point, id, measure);
boundPoints.add(id);
mass = 1;
}
/**
* Create an initial Canopy, retaining the original type of the given point
* (e.g. NamedVector)
*
* @param point
* a Vector
* @param id
* an int
* @param measure
* a DistanceMeasure
* @return a MeanShiftCanopy
*/
public static MeanShiftCanopy initialCanopy(Vector point, int id,
DistanceMeasure measure) {
MeanShiftCanopy result = new MeanShiftCanopy(point, id, measure);
// overwrite center so original point type is retained
result.setCenter(point);
return result;
}
public IntArrayList getBoundPoints() {
return boundPoints;
}
/**
* The receiver overlaps the given canopy. Add my bound points to it.
*
* @param canopy
* an existing MeanShiftCanopy
* @param accumulateBoundPoints
* true to accumulate bound points from the canopy
*/
void merge(MeanShiftCanopy canopy, boolean accumulateBoundPoints) {
if (accumulateBoundPoints) {
boundPoints.addAllOf(canopy.boundPoints);
}
mass += canopy.mass;
}
/**
* The receiver touches the given canopy. Add respective centers with the
* given weights.
*
* @param canopy
* an existing MeanShiftCanopy
* @param weight
* double weight of the touching
*/
void touch(MeanShiftCanopy canopy, double weight) {
canopy.observe(getCenter(), weight * mass);
observe(canopy.getCenter(), weight * canopy.mass);
}
@Override
public void readFields(DataInput in) throws IOException {
super.readFields(in);
this.mass = in.readInt();
int numpoints = in.readInt();
this.boundPoints = new IntArrayList();
for (int i = 0; i < numpoints; i++) {
this.boundPoints.add(in.readInt());
}
this.mass = boundPoints.size();
}
@Override
public void write(DataOutput out) throws IOException {
super.write(out);
out.writeInt(mass);
out.writeInt(boundPoints.size());
for (int v : boundPoints.elements()) {
out.writeInt(v);
}
}
public MeanShiftCanopy shallowCopy() {
MeanShiftCanopy result = new MeanShiftCanopy();
result.setMeasure(this.getMeasure());
result.setId(this.getId());
result.setCenter(this.getCenter());
result.setRadius(this.getRadius());
result.setNumObservations(this.getNumObservations());
result.setBoundPoints(boundPoints);
result.setMass(mass);
return result;
}
@Override
public String asFormatString() {
return toString();
}
public void setBoundPoints(IntArrayList boundPoints) {
this.boundPoints = boundPoints;
}
@Override
public String getIdentifier() {
return (isConverged() ? "MSV-" : "MSC-") + getId();
}
@Override
public double pdf(VectorWritable vw) {
// MSCanopy membership is explicit via membership in boundPoints. Can't
// compute pdf for Arbitrary point
throw new UnsupportedOperationException();
}
}