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; import com.google.common.collect.Lists; import org.apache.mahout.common.distance.EuclideanDistanceMeasure; import org.apache.mahout.knn.search.BruteSearch; import org.apache.mahout.math.ConstantVector; import org.apache.mahout.math.DenseMatrix; import org.apache.mahout.math.Matrix; import org.apache.mahout.math.Vector; import org.apache.mahout.math.random.MultiNormal; import org.apache.mahout.math.random.Sampler; import org.apache.mahout.math.WeightedVector; import java.util.List; public class BruteSpeedCheck { private static final int VECTOR_DIMENSION = 250; private static final int REFERENCE_SIZE = 10000; private static final int QUERY_SIZE = 100; public static void main(String[] args) { Sampler<Vector> rand = new MultiNormal(new ConstantVector(1, VECTOR_DIMENSION)); List<WeightedVector> referenceVectors = Lists.newArrayListWithExpectedSize(REFERENCE_SIZE); for (int i = 0; i < REFERENCE_SIZE; ++i) { referenceVectors.add(new WeightedVector(rand.sample(), 1, i)); } System.out.printf("Generated reference matrix.\n"); List<WeightedVector> queryVectors = Lists.newArrayListWithExpectedSize(QUERY_SIZE); for (int i = 0; i < QUERY_SIZE; ++i) { queryVectors.add(new WeightedVector(rand.sample(), 1, i)); } System.out.printf("Generated query matrix.\n"); for (int threads : new int[] { 1, 2, 3, 4, 5, 6, 10, 20, 50 }) { for (int block : new int[] { 1, 10, 50 }) { BruteSearch search = new BruteSearch(new EuclideanDistanceMeasure()); search.addAll(referenceVectors); long t0 = System.nanoTime(); search.search(queryVectors, block, threads); long t1 = System.nanoTime(); System.out.printf("%d\t%d\t%.2f\n", threads, block, (t1 - t0) / 1e9); } } } }