Niche model in c

nichemodel.c

// gcc niche.c -o nm -lgsl -lgslcblas -O3 -DHAVE_INLINE
// clang niche.c -o nm -lgsl -lgslcblas -O3 -DHAVE_INLINE

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

int has_niche(double n, double c, double r) {
	int hl = 0;
	if ((n < c+r) && (n > c-r)) {
		hl = 1;
	}
	return hl;
}

int main(int argc, char *argv[]) {
	clock_t start, stop;
	// Initiate the GSL random number generator
	gsl_rng *rng = gsl_rng_alloc(gsl_rng_taus2);
	gsl_rng_set(rng, time(NULL));

	unsigned int S = 100;
	double C = 0.02;

	// Let's generate three arrays of n, r, and c
	double *n = (double*) malloc(S * sizeof(double));
	double *r = (double*) malloc(S * sizeof(double));
	double *c = (double*) malloc(S * sizeof(double));

	// We then generate random values of n
	int sp;
	for (sp = 0; sp < S; ++sp) {
		n[sp] = gsl_ran_flat (rng, 0.0, 1.0);
		r[sp] = n[sp]*gsl_ran_beta(rng, 1, 1/(2*C)-1);
		c[sp] = gsl_ran_flat(rng, r[sp]/2, n[sp]);
		printf ("%.4f %.4f %.4f\n", n[sp], c[sp], r[sp]);
	}

	for (int sp1 = 0; sp1 < S; ++sp1) {
		for (int sp2 = 0; sp2 < S; ++sp2) {
			printf("%d %d %d\n", sp1, sp2, has_niche(n[sp2], c[sp1], r[sp1]));
		}
	}

	gsl_rng_free(rng);
	return EXIT_SUCCESS;
}