package org.apache.solr.search.function.distance;
/**
* 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.
*/
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.search.Searcher;
import org.apache.lucene.spatial.DistanceUtils;
import org.apache.solr.common.SolrException;
import org.apache.solr.search.function.DocValues;
import org.apache.solr.search.function.MultiValueSource;
import org.apache.solr.search.function.ValueSource;
import java.io.IOException;
import java.util.Map;
/**
* Calculate the p-norm for a Vector. See http://en.wikipedia.org/wiki/Lp_space
* <p/>
* Common cases:
* <ul>
* <li>0 = Sparseness calculation</li>
* <li>1 = Manhattan distance</li>
* <li>2 = Euclidean distance</li>
* <li>Integer.MAX_VALUE = infinite norm</li>
* </ul>
*
* @see SquaredEuclideanFunction for the special case
*/
public class VectorDistanceFunction extends ValueSource {
protected MultiValueSource source1, source2;
protected float power;
protected float oneOverPower;
public VectorDistanceFunction(float power, MultiValueSource source1, MultiValueSource source2) {
if ((source1.dimension() != source2.dimension())) {
throw new SolrException(SolrException.ErrorCode.BAD_REQUEST, "Illegal number of sources");
}
this.power = power;
this.oneOverPower = 1 / power;
this.source1 = source1;
this.source2 = source2;
}
protected String name() {
return "dist";
}
/**
* Calculate the distance
*
* @param doc The current doc
* @param dv1 The values from the first MultiValueSource
* @param dv2 The values from the second MultiValueSource
* @return The distance
*/
protected double distance(int doc, DocValues dv1, DocValues dv2) {
//Handle some special cases:
double[] vals1 = new double[source1.dimension()];
double[] vals2 = new double[source1.dimension()];
dv1.doubleVal(doc, vals1);
dv2.doubleVal(doc, vals2);
return DistanceUtils.vectorDistance(vals1, vals2, power, oneOverPower);
}
@Override
public DocValues getValues(Map context, IndexReader reader) throws IOException {
final DocValues vals1 = source1.getValues(context, reader);
final DocValues vals2 = source2.getValues(context, reader);
return new DocValues() {
@Override
public byte byteVal(int doc) {
return (byte) doubleVal(doc);
}
@Override
public short shortVal(int doc) {
return (short) doubleVal(doc);
}
@Override
public float floatVal(int doc) {
return (float) doubleVal(doc);
}
@Override
public int intVal(int doc) {
return (int) doubleVal(doc);
}
@Override
public long longVal(int doc) {
return (long) doubleVal(doc);
}
@Override
public double doubleVal(int doc) {
return distance(doc, vals1, vals2);
}
@Override
public String strVal(int doc) {
return Double.toString(doubleVal(doc));
}
@Override
public String toString(int doc) {
StringBuilder sb = new StringBuilder();
sb.append(name()).append('(').append(power).append(',');
boolean firstTime = true;
sb.append(vals1.toString(doc)).append(',');
sb.append(vals2.toString(doc));
sb.append(')');
return sb.toString();
}
};
}
@Override
public void createWeight(Map context, Searcher searcher) throws IOException {
source1.createWeight(context, searcher);
source2.createWeight(context, searcher);
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (!(o instanceof VectorDistanceFunction)) return false;
VectorDistanceFunction that = (VectorDistanceFunction) o;
if (Float.compare(that.power, power) != 0) return false;
if (!source1.equals(that.source1)) return false;
if (!source2.equals(that.source2)) return false;
return true;
}
@Override
public int hashCode() {
int result = source1.hashCode();
result = 31 * result + source2.hashCode();
result = 31 * result + Float.floatToRawIntBits(power);
return result;
}
@Override
public String description() {
StringBuilder sb = new StringBuilder();
sb.append(name()).append('(').append(power).append(',');
sb.append(source1).append(',');
sb.append(source2);
sb.append(')');
return sb.toString();
}
}