org.apache.sysml.runtime.util.PoissonPRNGenerator Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of systemml Show documentation
Show all versions of systemml Show documentation
Declarative Machine Learning
/*
* 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.sysml.runtime.util;
import org.apache.commons.math3.distribution.PoissonDistribution;
import org.apache.commons.math3.random.SynchronizedRandomGenerator;
import org.apache.commons.math3.random.Well1024a;
/**
* Class that can generate a stream of random numbers from Poisson
* distribution with specified mean.
*/
public class PoissonPRNGenerator extends PRNGenerator
{
PoissonDistribution _pdist = null;
double _mean = Double.NaN;
public PoissonPRNGenerator() {
// default mean and default seed
super();
_mean = 1.0;
setup(_mean, seed);
}
public PoissonPRNGenerator(double mean)
{
// default seed
super();
_mean = mean;
setup(_mean, seed);
}
public void setup(double mean, long sd) {
seed = sd;
SynchronizedRandomGenerator srg = new SynchronizedRandomGenerator(new Well1024a());
srg.setSeed(seed);
_pdist = new PoissonDistribution(srg, _mean, PoissonDistribution.DEFAULT_EPSILON, PoissonDistribution.DEFAULT_MAX_ITERATIONS);
}
@Override
public void setSeed(long sd) {
setup(_mean, sd);
}
public void setMean(double mean) {
setup(mean, seed);
}
public double nextDouble() {
return (double) _pdist.sample();
}
}