maximum.c File Reference

Functions
int	main (int argc, char **argv)

Function Documentation

main()

int main	(	int	argc,
		char **	argv
	)

                               {
  if (argc < 3) {
    printf("Usage: 1.This 2.n 3.ndata\n");
    exit(EXIT_FAILURE);
  }
  Integer_t i, j, count;
  Integer_t const     n = atoi(argv[1]);
  Integer_t const ndata = atoi(argv[2]);
  Integer_t seed=0;
  double max, maxData;
  double rand, rand1, rand2;
  double x1 = 2;
  double thereshold = x1/(1.0+x1);
  double coeff = exp(x1)/(1+x1);
 
  Integer_t subMax;
  Integer_t *histogram;
  double mean, stddev;
  double binwidth=0.05;
 
  char str[100];
  char *filename = str;
 
  FILE *Infp;
  FILE *Outfp;
  sprintf(str, "Dist_maximum_%lld_raw.txt", n);
  Outfp = fopen(filename, "w");
  if (Outfp == NULL) {
    printf("Can't open a file %s\n", filename);
    exit(EXIT_FAILURE);
  }
  fprintf(Outfp, "#(n=%lld, seed=%lld) Distribution of maximum of |x| \n\n", n, seed);
 
  init_genrand(seed);
  maxData = NAN;
  mean    = 0;
  stddev  = 0;
  for(i = 0;i < ndata; ++i) {
    max = NAN;
    for(j = 0;j < n; ++j) {
      rand1 = genrand_real3();
      if(rand1 < thereshold) rand = (1.0+x1)*rand1;
      else rand = x1-log((1-rand1)*(1.0+x1));
      max = fmax(max, rand);
    }
    maxData = fmax(maxData, max);
    mean   += max;
    stddev += max*max;
    fprintf(Outfp, "%lld %le\n", i, max);
  }
  mean   /= (double)ndata;
  stddev /= (double)ndata;
  stddev  = sqrt( stddev -mean*mean );
  binwidth *= stddev;
  subMax  = (Integer_t)(maxData/binwidth) +1;
  histogram = alloc_ivector(subMax); for(i = 0;i < subMax; ++i) histogram[i] = 0;
 
  sprintf(str, "Dist_maximum_%lld_raw.txt", n);
  Infp = fopen(filename, "r");
  if (Infp == NULL) {
    printf("Can't open a file %s\n", filename);
    exit(EXIT_FAILURE);
  }
  skip_header(Infp);
 
  count=0;
  while ( fscanf(Infp, "%lld %le", &i, &max) != EOF ) {
    histogram[ (Integer_t)(max/binwidth) ] += 1;
    count += 1;
  }
 
  sprintf(str, "Dist_maximum_%lld.txt", n);
  Outfp = fopen(filename, "w");
  if (Outfp == NULL) {
    printf("Can't open a file %s\n", filename);
    exit(EXIT_FAILURE);
  }
  fprintf(Outfp, "# mean=%le, stddev=%le\n\n", mean, stddev);
  fprintf(Outfp, "# 1.Maximum value 2.Probability density\n\n");
  for(i = 0;i < subMax; ++i) {
    fprintf(Outfp, "%le %le\n", binwidth*(i+0.5), histogram[i]/(binwidth*count));
  }
 
  return 0;
}