#include <stdio.h>
#include <math.h>
#include <stdlib.h>
#include <gsl/gsl_rng.h>
#include <gsl/gsl_randist.h>

int main(int argc, char *argv[])
{
  if (argc!=4) {
    fprintf(stderr,"Usage: %s <Iters> <Thin> <Seed>\n",argv[0]);
    exit(EXIT_FAILURE);
  }
  long N=(long) atoi(argv[1]);
  long thin=(long) atoi(argv[2]);
  long seed=(long) atoi(argv[3]);
  long i,j;
  gsl_rng *r = gsl_rng_alloc(gsl_rng_mt19937);
  gsl_rng_set(r,seed);
  double x=0;
  double y=0;
  printf("Iter x y\n");
  for (i=0;i<N;i++) {
    for (j=0;j<thin;j++) {
      x=gsl_ran_gamma(r,3.0,1.0/(y*y+4));
      y=1.0/(x+1)+gsl_ran_gaussian(r,1.0/sqrt(x+1));
    }
    printf("%ld %f %f\n",i,x,y);
  }
  exit(EXIT_SUCCESS);
}