Java tutorial
/* * 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.knn.search; import com.google.common.collect.Lists; import org.apache.commons.collections.ListUtils; import com.google.common.collect.Ordering; import org.apache.mahout.common.distance.EuclideanDistanceMeasure; import org.apache.mahout.knn.WeightedVector; import org.apache.mahout.math.DenseVector; import org.apache.mahout.math.Vector; import org.apache.mahout.math.function.DoubleFunction; import org.apache.mahout.math.function.Functions; import java.util.Collections; import java.util.List; public class ProjectionSearchEval { public void testSearch() { final EuclideanDistanceMeasure distance = new EuclideanDistanceMeasure(); for (int d = 20; d < 21; d++) { ProjectionSearch ps = new ProjectionSearch(20, distance, d, 1); List<Vector> ref = Lists.newArrayList(); final DoubleFunction random = Functions.random(); for (int i = 0; i < 40000; i++) { Vector v = new DenseVector(20); v.assign(random); ps.add(v, i); ref.add(v); } double sim = 0; int nSim = 0; double D1 = 0; double D2 = 0; double D3 = 0; int searchSize = 800; int returnSize = 100; List<Vector> randomNeighbor = Lists.newArrayList(); randomNeighbor.addAll(ref.subList(0, returnSize)); for (int i = 0; i < 100; i++) { // final Vector query = new DenseVector(ref.get(0)); final Vector query = new DenseVector(20); query.assign(random); Ordering<Vector> queryOrder = new Ordering<Vector>() { @Override public int compare(Vector v1, Vector v2) { return Double.compare(distance.distance(query, v1), distance.distance(query, v2)); } }; ps.setSearchSize(searchSize); List<WeightedVector> r = ps.search(query, returnSize); Collections.sort(ref, queryOrder); List<Vector> trueNeighbor = ref.subList(0, returnSize); List<WeightedVector> proxyNeighbor = r.subList(0, returnSize); List<Vector> intersection1 = ListUtils.intersection(trueNeighbor, proxyNeighbor); List<Vector> union1 = ListUtils.sum(trueNeighbor, proxyNeighbor); // double jaccardSim = intersection1.size() / (double)union1.size(); // sim += jaccardSim; sim += intersection1.size() / (double) returnSize; nSim++; double d1 = 0; double d2 = 0; double d3 = 0; for (int j = 0; j < returnSize; j++) { d1 += distance.distance(query, trueNeighbor.get(j)); d2 += distance.distance(query, proxyNeighbor.get(j)); d3 += distance.distance(query, randomNeighbor.get(j)); //System.out.print(distance.distance(query,trueNeighbor.get(j))); //System.out.print(" "); //System.out.println(distance.distance(query,randomNeighbor.get(j))); } d1 = d1 / returnSize; d2 = d2 / returnSize; d3 = d3 / returnSize; D1 += d1; D2 += d2; D3 += d3; /**** System.out.print(intersection1.size()); System.out.print(" "); System.out.print(union1.size()); System.out.print(" "); System.out.println(jaccardSim); *****/ } System.out.printf( "d=%d ave_sim=%.2f trueNeighbor_dist=%.2f proxyNeighbor_dist=%.2f randomNeighbor_dist=%.2f \n", d, sim / nSim, D1 / nSim, D2 / nSim, D3 / nSim); } } }