HypergeometricGen.java

/*
 * Class:        HypergeometricGen
 * Description:  random variate generators for the hypergeometric distribution
 * 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.*;
import umontreal.ssj.probdist.*;

public class HypergeometricGen extends RandomVariateGenInt {
   private int m;
   private int l;
   private int k;

   public HypergeometricGen(RandomStream s, int m, int l, int k) {
      super(s, new HypergeometricDist(m, l, k));
      setParams(m, l, k);
   }

   public HypergeometricGen(RandomStream s, HypergeometricDist dist) {
      super(s, dist);
      if (dist != null)
         setParams(dist.getM(), dist.getL(), dist.getK());
   }

   public static int nextInt(RandomStream s, int m, int l, int k) {
      return HypergeometricDist.inverseF(m, l, k, s.nextDouble());
   }

   public int getM() {
      return m;
   }

   public int getL() {
      return l;
   }

   public int getK() {
      return k;
   }

   protected void setParams(int m, int l, int k) {
      if (l <= 0)
         throw new IllegalArgumentException("l must be greater than 0");
      if (m <= 0 || m > l)
         throw new IllegalArgumentException("m is invalid: 1<=m<l");
      if (k <= 0 || k > l)
         throw new IllegalArgumentException("k is invalid: 1<=k<l");
      this.m = m;
      this.l = l;
      this.k = k;
   }
}