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
019import org.apache.commons.rng.UniformRandomProvider;
020
021/**
022 * Sampling from a uniform distribution.
023 *
024 * @since 1.0
025 */
026public class ContinuousUniformSampler
027    extends SamplerBase
028    implements ContinuousSampler {
029    /** Lower bound. */
030    private final double lo;
031    /** Higher bound. */
032    private final double hi;
033    /** Underlying source of randomness. */
034    private final UniformRandomProvider rng;
035
036    /**
037     * @param rng Generator of uniformly distributed random numbers.
038     * @param lo Lower bound.
039     * @param hi Higher bound.
040     */
041    public ContinuousUniformSampler(UniformRandomProvider rng,
042                                    double lo,
043                                    double hi) {
044        super(null);
045        this.rng = rng;
046        this.lo = lo;
047        this.hi = hi;
048    }
049
050    /** {@inheritDoc} */
051    @Override
052    public double sample() {
053        final double u = rng.nextDouble();
054        return u * hi + (1 - u) * lo;
055    }
056
057    /** {@inheritDoc} */
058    @Override
059    public String toString() {
060        return "Uniform deviate [" + rng.toString() + "]";
061    }
062}