| /* |
| * 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.lucene.spatial.util; |
| |
| import java.io.IOException; |
| import java.util.Objects; |
| |
| import org.apache.lucene.index.LeafReaderContext; |
| import org.apache.lucene.search.DoubleValues; |
| import org.apache.lucene.search.DoubleValuesSource; |
| import org.apache.lucene.search.Explanation; |
| import org.apache.lucene.search.IndexSearcher; |
| |
| /** |
| * Transforms a DoubleValuesSource using the formula v = k / (v + k) |
| */ |
| public class ReciprocalDoubleValuesSource extends DoubleValuesSource { |
| |
| private final double distToEdge; |
| private final DoubleValuesSource input; |
| |
| /** |
| * Creates a ReciprocalDoubleValuesSource |
| * @param distToEdge the value k in v = k / (v + k) |
| * @param input the input DoubleValuesSource to transform |
| */ |
| public ReciprocalDoubleValuesSource(double distToEdge, DoubleValuesSource input) { |
| this.distToEdge = distToEdge; |
| this.input = input; |
| } |
| |
| @Override |
| public DoubleValues getValues(LeafReaderContext ctx, DoubleValues scores) throws IOException { |
| DoubleValues in = input.getValues(ctx, scores); |
| return new DoubleValues() { |
| @Override |
| public double doubleValue() throws IOException { |
| return recip(in.doubleValue()); |
| } |
| |
| @Override |
| public boolean advanceExact(int doc) throws IOException { |
| return in.advanceExact(doc); |
| } |
| }; |
| } |
| |
| private double recip(double in) { |
| return distToEdge / (in + distToEdge); |
| } |
| |
| @Override |
| public boolean needsScores() { |
| return input.needsScores(); |
| } |
| |
| @Override |
| public boolean isCacheable(LeafReaderContext ctx) { |
| return input.isCacheable(ctx); |
| } |
| |
| @Override |
| public Explanation explain(LeafReaderContext ctx, int docId, Explanation scoreExplanation) throws IOException { |
| Explanation expl = input.explain(ctx, docId, scoreExplanation); |
| return Explanation.match(recip(expl.getValue().doubleValue()), |
| distToEdge + " / (v + " + distToEdge + "), computed from:", expl); |
| } |
| |
| @Override |
| public DoubleValuesSource rewrite(IndexSearcher searcher) throws IOException { |
| return new ReciprocalDoubleValuesSource(distToEdge, input.rewrite(searcher)); |
| } |
| |
| @Override |
| public boolean equals(Object o) { |
| if (this == o) return true; |
| if (o == null || getClass() != o.getClass()) return false; |
| ReciprocalDoubleValuesSource that = (ReciprocalDoubleValuesSource) o; |
| return Double.compare(that.distToEdge, distToEdge) == 0 && |
| Objects.equals(input, that.input); |
| } |
| |
| @Override |
| public int hashCode() { |
| return Objects.hash(distToEdge, input); |
| } |
| |
| @Override |
| public String toString() { |
| return "recip(" + distToEdge + ", " + input.toString() + ")"; |
| } |
| } |