/* File : Test.c          */
/* Author : Eric Thiemard */
/* Version : 14.12.98     */
/* Language : C           */

/* Related paper : Eric Thiemard "Economic Generation of Low- */
/* Discrepancy Sequences with a b-ary Gray Code". Submitted   */
/* in december 1998 to TOMACS : ACM Transactions on Modeling  */
/* and Computer Simulation.                                   */

/* This test routine is part of the GrayFaure package. Given  */
/* a dimension s, a number of iterations N, and a skip value, */ 
/* it generates and prints N points of a s-dimensional Faure  */
/* low-discrepancy sequence in base b (the smallest prime>=s) */
/* skipping the first b^skip points. The sequence is shuffled */
/* with a b-ary Gray code.                                    */

#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include "GrayFaure.h"

static void usage(char *s)
{
  fprintf(stderr,"Usage: %s \"Dimension>=2\"\
 \"Iterations\" \"0<=Skip<floor(ln(LONG_MAX)/ln(base))\"\n",s);
  exit(EXIT_FAILURE);
}

int main(int argc, char *argv[])
{
  long *Faure;
  int dimension;
  int iterations;
  int skip;
  int base;
  int i;

  if (argc!=4)
    usage(argv[0]);
  dimension = atoi(argv[1]);
  iterations = atoi(argv[2]);
  skip = atoi(argv[3]);
  base = GrayFaureInit(dimension,skip);
  if (base==0)
    usage(argv[0]);

  printf("Dimension %d, base %d, skipping %ld point(s) (starting from 0)\n",\
dimension,base,(long) pow((double) base,(double) skip));

  for (;iterations>0;iterations--)
    {
      Faure = GrayFaureNext();
      if (Faure==NULL)
	{
	  fprintf(stderr,"Maximum index reached ; skip might be too high.\n");
	  exit(EXIT_FAILURE);
	}
      for (i=0;i<dimension;i++)
	printf("%E ",(float) Faure[i]/Faure[dimension]);
      printf("\n");
    }
  return EXIT_SUCCESS;
}