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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 <isl_ctx_private.h>
#include <isl_map_private.h>
#include <isl/lp.h>
#include "isl_lp_piplib.h"
#include <isl/seq.h>
#include "isl_tab.h"
enum isl_lp_result isl_tab_solve_lp(struct isl_basic_map *bmap, int maximize,
isl_int *f, isl_int denom, isl_int *opt,
isl_int *opt_denom,
struct isl_vec **sol)
{
struct isl_tab *tab;
enum isl_lp_result res;
unsigned dim = isl_basic_map_total_dim(bmap);
if (maximize)
isl_seq_neg(f, f, 1 + dim);
bmap = isl_basic_map_gauss(bmap, NULL);
tab = isl_tab_from_basic_map(bmap);
res = isl_tab_min(tab, f, denom, opt, opt_denom, 0);
if (res == isl_lp_ok && sol) {
*sol = isl_tab_get_sample_value(tab);
if (!*sol)
res = isl_lp_error;
}
isl_tab_free(tab);
if (maximize)
isl_seq_neg(f, f, 1 + dim);
if (maximize && opt)
isl_int_neg(*opt, *opt);
return res;
}
/* Given a basic map "bmap" and an affine combination of the variables "f"
* with denominator "denom", set *opt / *opt_denom to the minimal
* (or maximal if "maximize" is true) value attained by f/d over "bmap",
* assuming the basic map is not empty and the expression cannot attain
* arbitrarily small (or large) values.
* If opt_denom is NULL, then *opt is rounded up (or down)
* to the nearest integer.
* The return value reflects the nature of the result (empty, unbounded,
* minmimal or maximal value returned in *opt).
*/
enum isl_lp_result isl_basic_map_solve_lp(struct isl_basic_map *bmap, int max,
isl_int *f, isl_int d, isl_int *opt,
isl_int *opt_denom,
struct isl_vec **sol)
{
if (sol)
*sol = NULL;
if (!bmap)
return isl_lp_error;
switch (bmap->ctx->opt->lp_solver) {
case ISL_LP_PIP:
return isl_pip_solve_lp(bmap, max, f, d, opt, opt_denom, sol);
case ISL_LP_TAB:
return isl_tab_solve_lp(bmap, max, f, d, opt, opt_denom, sol);
default:
return isl_lp_error;
}
}
enum isl_lp_result isl_basic_set_solve_lp(struct isl_basic_set *bset, int max,
isl_int *f, isl_int d, isl_int *opt,
isl_int *opt_denom,
struct isl_vec **sol)
{
return isl_basic_map_solve_lp((struct isl_basic_map *)bset, max,
f, d, opt, opt_denom, sol);
}
enum isl_lp_result isl_map_solve_lp(__isl_keep isl_map *map, int max,
isl_int *f, isl_int d, isl_int *opt,
isl_int *opt_denom,
struct isl_vec **sol)
{
int i;
isl_int o;
isl_int t;
isl_int opt_i;
isl_int opt_denom_i;
enum isl_lp_result res;
int max_div;
isl_vec *v = NULL;
if (!map)
return isl_lp_error;
if (map->n == 0)
return isl_lp_empty;
max_div = 0;
for (i = 0; i < map->n; ++i)
if (map->p[i]->n_div > max_div)
max_div = map->p[i]->n_div;
if (max_div > 0) {
unsigned total = isl_dim_total(map->dim);
v = isl_vec_alloc(map->ctx, 1 + total + max_div);
if (!v)
return isl_lp_error;
isl_seq_cpy(v->el, f, 1 + total);
isl_seq_clr(v->el + 1 + total, max_div);
f = v->el;
}
if (!opt && map->n > 1 && sol) {
isl_int_init(o);
opt = &o;
}
if (map->n > 0)
isl_int_init(opt_i);
if (map->n > 0 && opt_denom) {
isl_int_init(opt_denom_i);
isl_int_init(t);
}
res = isl_basic_map_solve_lp(map->p[0], max, f, d,
opt, opt_denom, sol);
if (res == isl_lp_error || res == isl_lp_unbounded)
goto done;
if (sol)
*sol = NULL;
for (i = 1; i < map->n; ++i) {
isl_vec *sol_i = NULL;
enum isl_lp_result res_i;
int better;
res_i = isl_basic_map_solve_lp(map->p[i], max, f, d,
&opt_i,
opt_denom ? &opt_denom_i : NULL,
sol ? &sol_i : NULL);
if (res_i == isl_lp_error || res_i == isl_lp_unbounded) {
res = res_i;
goto done;
}
if (res_i == isl_lp_empty)
continue;
if (res == isl_lp_empty) {
better = 1;
} else if (!opt_denom) {
if (max)
better = isl_int_gt(opt_i, *opt);
else
better = isl_int_lt(opt_i, *opt);
} else {
isl_int_mul(t, opt_i, *opt_denom);
isl_int_submul(t, *opt, opt_denom_i);
if (max)
better = isl_int_is_pos(t);
else
better = isl_int_is_neg(t);
}
if (better) {
res = res_i;
if (opt)
isl_int_set(*opt, opt_i);
if (opt_denom)
isl_int_set(*opt_denom, opt_denom_i);
if (sol) {
isl_vec_free(*sol);
*sol = sol_i;
}
} else
isl_vec_free(sol_i);
}
done:
isl_vec_free(v);
if (map->n > 0 && opt_denom) {
isl_int_clear(opt_denom_i);
isl_int_clear(t);
}
if (map->n > 0)
isl_int_clear(opt_i);
if (opt == &o)
isl_int_clear(o);
return res;
}
enum isl_lp_result isl_set_solve_lp(__isl_keep isl_set *set, int max,
isl_int *f, isl_int d, isl_int *opt,
isl_int *opt_denom,
struct isl_vec **sol)
{
return isl_map_solve_lp((struct isl_map *)set, max,
f, d, opt, opt_denom, sol);
}
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