Simple genetic algorithm

ga.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#define POP_SIZE 4096
#define STEP 96
#define UNIFORM_RATE 0.5
#define MUTATION_RATE 0.15
#define TOURNAMENT_SIZE 15
#define ELITISM 1
#define RANDBETWEEN(A,B) A + rand()/(RAND_MAX/(B - A))
#define CHANCE(A) rand() < A * RAND_MAX

static void pretty_print(char *string) {
    for(string; *string != '\0'; ++string) {
        printf("%c", *string);
    }
    printf("\n");
}

static int fitness(char* solution, char* gene) {
    int fitness = 0;
    for(solution; *solution != '\0'; ++solution, ++gene) {
        if(*solution == *gene)
            fitness++;
    }
    return fitness;
}

static char* fittest(char* population, char *solution) {
    int cur_fitness = 0;
    int max_fitness = 0;
    char *p = malloc(sizeof(*p) * (STEP + 1));
    for(population; *population != '\0'; population += STEP) {
        cur_fitness = fitness(solution, population);
        if(cur_fitness >= max_fitness) {
            max_fitness = cur_fitness;
            memcpy(p, population, STEP);
        }
    }
    return p;
}

static void mutate(char* gene) {
    for(gene; *gene != '\0'; ++gene) {
        if(RANDBETWEEN(0.0, 1.0) <= MUTATION_RATE) {
            *gene = RANDBETWEEN(0, 2) + '0';
        }
    }
}

static char* crossover(char* individual1, char* individual2) {
    char *p = malloc(sizeof(*p) * (STEP + 1));
    int i = 0;
    for(i = 0; i < strlen(individual1); ++i) {
        if(RANDBETWEEN(0.0, 1.0) <= UNIFORM_RATE) {
            memcpy(p+i, individual1+i, 1);
        } else {
            memcpy(p+i, individual2+i, 1);
        }
    }
    return p;
}

static char* tournament_selection(char *population, char *solution) {
    int i = 0;
    char p[TOURNAMENT_SIZE * STEP];
    for(i; i < TOURNAMENT_SIZE*STEP; i += STEP) {
        memcpy(p+i, population+(RANDBETWEEN(0, strlen(population) / STEP)), STEP);
    }
    return fittest(p, solution);
}

static char* evolve(char* population, char* solution) {
    char *p = malloc(sizeof(*p) * (POP_SIZE + 1));
    int i = 0;
    if(ELITISM) {
        char *f = fittest(population, solution);
        memcpy(p, f, STEP);
        free(f);
        i += STEP;
    }
    for(i; i < POP_SIZE - STEP; i += STEP) {
        char *gene_1 = tournament_selection(population, solution);
        char *gene_2 = tournament_selection(population, solution);
        char *new_gene = crossover(gene_1, gene_2);
        mutate(new_gene);
        memcpy(p+i, new_gene, STEP);
        free(gene_1);
        free(gene_2);
        free(new_gene);
    }
    return p;
}

int main(int argv, char** argc) {
    srand((unsigned int)time(NULL));
    char a[STEP];
    int i = 0;
    for(i = 0; i < STEP; ++i) {
        *(a + i) = RANDBETWEEN(0, 2) + '0';
    }
    char population[POP_SIZE];
    for(i = 0; i < POP_SIZE; ++i) {
        *(population + i) = RANDBETWEEN(0, 2) + '0';
    }
    int generations = 0;
    int fit = 0;
    int loop = 1;
    while(loop == 1) {
        char *fittest_gene = fittest(population, a);
        fit = fitness(a, fittest_gene);
        generations++;
        printf("Generation: %d Fitness: %d\n", generations, fit);
        free(fittest_gene);
        if(fit == STEP) {
            loop = 0;
        } else {
            char *new_pop = evolve(population, a);
            memcpy(population, new_pop, POP_SIZE);
            free(new_pop);
        }
    }
    return 0;
}