RandomVariateGen.java

/*
 * Class:        RandomVariateGen
 * Description:  base class for all random variate generators over the reals 
 * Environment:  Java
 * Software:     SSJ 
 * Copyright (C) 2001  Pierre L'Ecuyer and Universite de Montreal
 * Organization: DIRO, Universite de Montreal
 * @author       
 * @since
 *
 *
 * Licensed 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 umontreal.ssj.randvar;
 
import umontreal.ssj.rng.RandomStream;
import umontreal.ssj.probdist.Distribution;

public class RandomVariateGen {
 
   protected RandomStream stream;
   // the stream used for generating random variates
 
   protected Distribution dist;
   // the distribution used by this generator
 
   // This constructor is needed for subclasses with no associated distribution.
   protected RandomVariateGen() {
   }

   public RandomVariateGen(RandomStream s, Distribution dist) {
      this.stream = s;
      this.dist = dist;
   }

   public double nextDouble() {
      return dist.inverseF(stream.nextDouble());
   }

   public void nextArrayOfDouble(double[] v, int start, int n) {
      if (n <= 0)
         throw new IllegalArgumentException("n must be positive.");
      for (int i = 0; i < n; i++)
         v[start + i] = nextDouble();
   }

   public double[] nextArrayOfDouble(int n) {
      if (n <= 0)
         throw new IllegalArgumentException("n must be positive.");
      double[] v = new double[n];
      for (int i = 0; i < n; i++)
         v[i] = nextDouble();
      return v;
   }

   public RandomStream getStream() {
      return stream;
   }

   public void setStream(RandomStream stream) {
      this.stream = stream;
   }

   public Distribution getDistribution() {
      return dist;
   }

   public String toString() {
      if (dist != null)
         return getClass().getSimpleName() + " with  " + dist.toString();
      else
         return getClass().getSimpleName();
   }
 
}