knapsack-sga.c

/* knapsack-sga.c
 *
 * (C) 2018 Carlos M. Fonseca <cmfonsec@dei.uc.pt>
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or (at
 * your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */
 
#include <stdlib.h>
#include <stdio.h>
#include <time.h>
#include <gsl/gsl_rng.h>
#include "knapsack.h"
#include "sga.h"
 
gsl_rng *rng;    /* The single rng instance used by the whole code */
 
int main(int argc, char **argv) {
    struct problem *p;
    struct solverState *ss;
    int max_iter, pop_size, i;
    double cost, mincost;
 
    if (argc < 4) {
        fprintf(stderr, "Usage: %s <file name> <pop size> <max iter>\n", argv[0]);
        return 0;
    }
 
    /* Set up random number generation */
    rng = gsl_rng_alloc(gsl_rng_mt19937); 
    gsl_rng_set(rng, time(0));
 
    /* Input arguments */
    pop_size = atoi(argv[2]);
    max_iter = atoi(argv[3]);
 
    /* Problem and solver instantiation */
    p = newProblem(argv[1]);
    if (p != NULL) {
        ss = newSolver(p, pop_size);
 
#if 0
        /* Custom parameters */
        setRecombinationRate(ss, 0.);
        setMutationRate(ss, (1.-1./getSelectivePressure(ss))*.8);
#endif
 
        /* Run */
        mincost = getObjectiveValue(getSolverSolution(ss));
        printf("iter = 0, obj = %.0f\n", mincost);
        for (i = 0; i < max_iter; i++) {
            nextSolverState(ss);
            cost = getObjectiveValue(getSolverSolution(ss));
            if (cost < mincost) {
                mincost = cost;
                printf("iter = %d, obj = %.0f\n", i+1, mincost);
            }
        }
 
        /* Report result */
        printSolution(getSolverSolution(ss));
 
        /* Clean up */
        freeSolver(ss);
        freeProblem(p);
    }
    gsl_rng_free(rng);
    return 0;
}