001 /* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 package org.apache.commons.math3.distribution; 018 019 import org.apache.commons.math3.exception.NotStrictlyPositiveException; 020 import org.apache.commons.math3.exception.util.LocalizedFormats; 021 import org.apache.commons.math3.random.RandomGenerator; 022 023 /** 024 * Base class for multivariate probability distributions. 025 * 026 * @version $Id: AbstractMultivariateRealDistribution.java 1416643 2012-12-03 19:37:14Z tn $ 027 * @since 3.1 028 */ 029 public abstract class AbstractMultivariateRealDistribution 030 implements MultivariateRealDistribution { 031 /** RNG instance used to generate samples from the distribution. */ 032 protected final RandomGenerator random; 033 /** The number of dimensions or columns in the multivariate distribution. */ 034 private final int dimension; 035 036 /** 037 * @param rng Random number generator. 038 * @param n Number of dimensions. 039 */ 040 protected AbstractMultivariateRealDistribution(RandomGenerator rng, 041 int n) { 042 random = rng; 043 dimension = n; 044 } 045 046 /** {@inheritDoc} */ 047 public void reseedRandomGenerator(long seed) { 048 random.setSeed(seed); 049 } 050 051 /** {@inheritDoc} */ 052 public int getDimension() { 053 return dimension; 054 } 055 056 /** {@inheritDoc} */ 057 public abstract double[] sample(); 058 059 /** {@inheritDoc} */ 060 public double[][] sample(final int sampleSize) { 061 if (sampleSize <= 0) { 062 throw new NotStrictlyPositiveException(LocalizedFormats.NUMBER_OF_SAMPLES, 063 sampleSize); 064 } 065 final double[][] out = new double[sampleSize][dimension]; 066 for (int i = 0; i < sampleSize; i++) { 067 out[i] = sample(); 068 } 069 return out; 070 } 071 }