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#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include "genalg.h"
struct organism_t {
double fitness, a, b;
};
double randf() {
return 2.0 * (((double)rand())/RAND_MAX) - 1.0;
}
struct organism_t * org_alloc(int randomize) {
struct organism_t * org = malloc(sizeof(struct organism_t));
if (org == NULL) {
fprintf(stderr, "failed to allocate organism!\n");
return NULL;
}
org->fitness = -1;
org->a = 0;
org->b = 0;
if (randomize) {
org->a = 20.0 * randf();
org->b = 20.0 * randf();
}
return org;
}
double org_fitness(void *ptr) {
struct organism_t *org = ptr;
if (org->fitness >= 0) {
return org->fitness;
} else {
double error = pow(org->a - 14.0, 2) + pow(org->b + 7.0, 2);
org->fitness = 1.0/(fabs(error)+1);
return org->fitness;
}
}
void * create_child(void *ptr) {
struct organism_t *org = ptr;
struct organism_t *child = org_alloc(0);
if (child == NULL) {
return NULL;
}
child->a = org->a + 0.1*randf();
child->b = org->b + 0.1*randf();
return child;
}
int main() {
genalg_t *ga = ga_create(1000, org_fitness, create_child, free);
for (size_t i=0; i<ga->pop_count; i++) {
ga->population[i] = org_alloc(1);
}
struct genalg_stats_t stats;
for (int i=0; i<100; i++) {
ga_replace_population(ga, 60, 50);
stats = ga_population_statistics(ga);
struct organism_t *org = stats.best;
printf(
"mean: %f, variance: %f\nmin: %f, max: %f\nbest: (%f, %f)\n",
stats.mean, stats.variance, stats.min, stats.max,
org->a, org->b
);
}
ga_free(ga);
return 0;
}
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