polyhedron_minimize.c
2.38 KB
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/*
* Copyright 2008-2009 Katholieke Universiteit Leuven
*
* Use of this software is governed by the MIT 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_private.h>
#include <isl_seq.h>
#include <isl_vec_private.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;
}