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 */
017package org.apache.commons.rng.sampling.distribution;
018
019/**
020 * Sampling from a Gaussian distribution with given mean and
021 * standard deviation.
022 *
023 * @since 1.1
024 */
025public class GaussianSampler implements ContinuousSampler {
026    /** Mean. */
027    private final double mean;
028    /** standardDeviation. */
029    private final double standardDeviation;
030    /** Normalized Gaussian sampler. */
031    private final NormalizedGaussianSampler normalized;
032
033    /**
034     * @param normalized Generator of N(0,1) Gaussian distributed random numbers.
035     * @param mean Mean of the Gaussian distribution.
036     * @param standardDeviation Standard deviation of the Gaussian distribution.
037     */
038    public GaussianSampler(NormalizedGaussianSampler normalized,
039                           double mean,
040                           double standardDeviation) {
041        this.normalized = normalized;
042        this.mean = mean;
043        this.standardDeviation = standardDeviation;
044    }
045
046    /** {@inheritDoc} */
047    @Override
048    public double sample() {
049        return standardDeviation * normalized.sample() + mean;
050    }
051
052    /** {@inheritDoc} */
053    @Override
054    public String toString() {
055        return "Gaussian deviate [" + normalized.toString() + "]";
056    }
057}