/* This program helps you make QQ plots, by generating the       */
/* quantiles from the desired theoretical distributions.         */
/* Written by Carey Williamson for CPSC 531 in November 2017     */

/* Usage: cc -o qq qq.c -lm                                      */
/*        qq                                                     */

#include <stdio.h>
#include <stdlib.h>
#include <math.h> /* use man 3 log for the math functions */

#define GRANULARITY 0.01

#define A 10.0  /* left edge of Uniform distribution */
#define B 80.0  /* right edge of Uniform distribution */
#define P 0.1 /* parameter of Geometric distribution */
#define MU 15.0 /* mean of Exponential distribution */
#define ALPHA 1.0 /* tail index of Pareto distribution */

int main()
  {
    int i;
    float x, value;

    x = 0.0;
    while( x <= 1.0 )
      {
	value = A + floor((B-A+1)*x);    /* for EquiLikely(A,B) */
	value = x;    /* for Uniform(0,1) */
	value = floor(log(1-x)/log(1-P));    /* for Geometric(P) */
	value = A + (B-A)*x;    /* for Uniform(A,B) */
	value = 1/pow((1-x), 1/ALPHA);    /* for Pareto(ALPHA) */
	value = -MU*log(1-x);    /* for Exponential(MU) */
	printf("%f %f\n", value, x);
	x += GRANULARITY;
      }
  }