nexmon – Rev 1

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/*
 * Copyright 2008-2009 Katholieke Universiteit Leuven
 *
 * Use of this software is governed by the GNU LGPLv2.1 license
 *
 * Written by Sven Verdoolaege, K.U.Leuven, Departement
 * Computerwetenschappen, Celestijnenlaan 200A, B-3001 Leuven, Belgium
 */

#include <assert.h>
#include <isl/set.h>
#include <isl/vec.h>
#include <isl/ilp.h>
#include <isl/seq.h>

/* The input of this program is the same as that of the "polytope_minimize"
 * program from the barvinok distribution.
 *
 * Constraints of set is PolyLib format.
 * Linear or affine objective function in PolyLib format.
 */

static struct isl_vec *isl_vec_lin_to_aff(struct isl_vec *vec)
{
        struct isl_vec *aff;

        if (!vec)
                return NULL;
        aff = isl_vec_alloc(vec->ctx, 1 + vec->size);
        if (!aff)
                goto error;
        isl_int_set_si(aff->el[0], 0);
        isl_seq_cpy(aff->el + 1, vec->el, vec->size);
        isl_vec_free(vec);
        return aff;
error:
        isl_vec_free(vec);
        return NULL;
}

/* Rotate elements of vector right.
 * In particular, move the constant term from the end of the
 * vector to the start of the vector.
 */
static struct isl_vec *vec_ror(struct isl_vec *vec)
{
        int i;

        if (!vec)
                return NULL;
        for (i = vec->size - 2; i >= 0; --i)
                isl_int_swap(vec->el[i], vec->el[i + 1]);
        return vec;
}

int main(int argc, char **argv)
{
        struct isl_ctx *ctx = isl_ctx_alloc();
        struct isl_basic_set *bset;
        struct isl_vec *obj;
        struct isl_vec *sol;
        isl_int opt;
        unsigned dim;
        enum isl_lp_result res;
        isl_printer *p;

        isl_int_init(opt);
        bset = isl_basic_set_read_from_file(ctx, stdin);
        assert(bset);
        obj = isl_vec_read_from_file(ctx, stdin);
        assert(obj);
        dim = isl_basic_set_total_dim(bset);
        assert(obj->size >= dim && obj->size <= dim + 1);
        if (obj->size != dim + 1)
                obj = isl_vec_lin_to_aff(obj);
        else
                obj = vec_ror(obj);
        res = isl_basic_set_solve_ilp(bset, 0, obj->el, &opt, &sol);
        switch (res) {
        case isl_lp_error:
                fprintf(stderr, "error\n");
                return -1;
        case isl_lp_empty:
                fprintf(stdout, "empty\n");
                break;
        case isl_lp_unbounded:
                fprintf(stdout, "unbounded\n");
                break;
        case isl_lp_ok:
                p = isl_printer_to_file(ctx, stdout);
                p = isl_printer_print_vec(p, sol);
                p = isl_printer_end_line(p);
                p = isl_printer_print_isl_int(p, opt);
                p = isl_printer_end_line(p);
                isl_printer_free(p);
        }
        isl_basic_set_free(bset);
        isl_vec_free(obj);
        isl_vec_free(sol);
        isl_ctx_free(ctx);
        isl_int_clear(opt);

        return 0;
}