KorobovLattice.java

/*
 * Class:        KorobovLattice
 * Description:  Korobov lattice
 * 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.hups;
 
import umontreal.ssj.util.PrintfFormat;

public class KorobovLattice extends Rank1Lattice {
   protected int genA; // multiplier a
   private int genT; // shift t
 
   private void initN(int n, int t) {
      int a = (genA % n) + (genA < 0 ? n : 0);
      genT = t;
      long[] B = new long[dim];
      B[0] = 1;
      int j;
      for (j = 0; j < t; j++)
         B[0] *= a;
      v[0] = B[0] * normFactor;
      for (j = 1; j < dim; j++) {
         B[j] = (a * B[j - 1]) % n;
         v[j] = normFactor * B[j];
      }
   }

   public KorobovLattice(int n, int a, int s) {
      super(n, null, 0);
      genA = a;
      dim = s;
      v = new double[s];
      initN(n, 0);
   }

   public KorobovLattice(int n, int a, int s, int t) {
      super(n, null, 0);
      if (t < 0)
         throw new IllegalArgumentException("KorobovLattice: must have t >= 0");
      dim = s;
      genA = a;
      v = new double[s];
      initN(n, t);
   }

   public void setNumPoints(int n) {
      initN(n, genT);
   }

   public int getA() {
      return genA;
   }
 
   public String toString() {
      StringBuffer sb = new StringBuffer("KorobovLattice:" + PrintfFormat.NEWLINE);
      sb.append("Multiplier a: " + genA + PrintfFormat.NEWLINE);
      sb.append(super.toString());
      return sb.toString();
   }
}