/*
* 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 com.mapr.stats.random;
import org.apache.mahout.math.jet.random.AbstractContinousDistribution;
import java.util.Random;
public class BinomialDistributionSampler extends DistributionGenerator {
private final BetaDistribution bd;
private final Random gen;
public BinomialDistributionSampler(double alpha, double beta, Random gen) {
this.gen = gen;
bd = new BetaDistribution(alpha, beta);
}
@Override
public DistributionWithMean nextDistribution() {
final double p = bd.nextDouble();
return new DistributionWithMean(new AbstractContinousDistribution() {
@Override
public double nextDouble() {
return gen.nextDouble() < p ? 1 : 0;
}
}, p);
}
}