+/*
+ * 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_seq.h"
+#include <isl_map_private.h>
+#include <isl/seq.h>
#include "isl_tab.h"
struct tab_lp {
isl_int *obj;
isl_int opt;
isl_int opt_denom;
+ isl_int tmp;
+ isl_int tmp2;
int neq;
unsigned dim;
/* number of constraints in initial product tableau */
int con_offset;
+ /* objective function has fixed or no integer value */
+ int is_fixed;
};
-static struct tab_lp *init_lp(struct isl_basic_set *bset);
+static struct tab_lp *init_lp(struct isl_tab *tab);
static void set_lp_obj(struct tab_lp *lp, isl_int *row, int dim);
static int solve_lp(struct tab_lp *lp);
static void get_obj_val(struct tab_lp* lp, mpq_t *F);
static void delete_lp(struct tab_lp *lp);
static int add_lp_row(struct tab_lp *lp, isl_int *row, int dim);
static void get_alpha(struct tab_lp* lp, int row, mpq_t *alpha);
-static void del_lp_row(struct tab_lp *lp);
+static int del_lp_row(struct tab_lp *lp) WARN_UNUSED;
+static int cut_lp_to_hyperplane(struct tab_lp *lp, isl_int *row);
#define GBR_LP struct tab_lp
#define GBR_type mpq_t
#define GBR_set_ui(a,b) mpq_set_ui(a,b,1)
#define GBR_mul(a,b,c) mpq_mul(a,b,c)
#define GBR_lt(a,b) (mpq_cmp(a,b) < 0)
+#define GBR_is_zero(a) (mpq_sgn(a) == 0)
#define GBR_floor(a,b) mpz_fdiv_q(a,mpq_numref(b),mpq_denref(b))
#define GBR_ceil(a,b) mpz_cdiv_q(a,mpq_numref(b),mpq_denref(b))
#define GBR_lp_init(P) init_lp(P)
#define GBR_lp_next_row(lp) lp->neq
#define GBR_lp_add_row(lp, row, dim) add_lp_row(lp, row, dim)
#define GBR_lp_get_alpha(lp, row, alpha) get_alpha(lp, row, alpha)
-#define GBR_lp_del_row(lp) del_lp_row(lp);
+#define GBR_lp_del_row(lp) del_lp_row(lp)
+#define GBR_lp_is_fixed(lp) (lp)->is_fixed
+#define GBR_lp_cut(lp, obj) cut_lp_to_hyperplane(lp, obj)
#include "basis_reduction_templ.c"
/* Set up a tableau for the Cartesian product of bset with itself.
* This could be optimized by first setting up a tableau for bset
* and then performing the Cartesian product on the tableau.
*/
-static struct isl_tab *gbr_tab(struct isl_basic_set *bset,
- struct isl_vec *row)
+static struct isl_tab *gbr_tab(struct isl_tab *tab, struct isl_vec *row)
{
- int i, j;
unsigned dim;
- struct isl_tab *tab;
+ struct isl_tab *prod;
- if (!bset || !row)
+ if (!tab || !row)
return NULL;
- dim = isl_basic_set_total_dim(bset);
- tab = isl_tab_alloc(bset->ctx, 2 * bset->n_ineq + dim + 1, 2 * dim, 0);
-
- for (i = 0; i < 2; ++i) {
- isl_seq_clr(row->el + 1 + (1 - i) * dim, dim);
- for (j = 0; j < bset->n_ineq; ++j) {
- isl_int_set(row->el[0], bset->ineq[j][0]);
- isl_seq_cpy(row->el + 1 + i * dim,
- bset->ineq[j] + 1, dim);
- tab = isl_tab_add_ineq(tab, row->el);
- if (!tab || tab->empty)
- return tab;
- }
+ dim = tab->n_var;
+ prod = isl_tab_product(tab, tab);
+ if (isl_tab_extend_cons(prod, 3 * dim + 1) < 0) {
+ isl_tab_free(prod);
+ return NULL;
}
-
- return tab;
+ return prod;
}
-static struct tab_lp *init_lp(struct isl_basic_set *bset)
+static struct tab_lp *init_lp(struct isl_tab *tab)
{
struct tab_lp *lp = NULL;
- if (!bset)
+ if (!tab)
return NULL;
- isl_assert(bset->ctx, bset->n_eq == 0, return NULL);
-
- lp = isl_calloc_type(bset->ctx, struct tab_lp);
+ lp = isl_calloc_type(tab->mat->ctx, struct tab_lp);
if (!lp)
return NULL;
isl_int_init(lp->opt);
isl_int_init(lp->opt_denom);
+ isl_int_init(lp->tmp);
+ isl_int_init(lp->tmp2);
- lp->dim = isl_basic_set_total_dim(bset);
+ lp->dim = tab->n_var;
- lp->ctx = bset->ctx;
+ lp->ctx = tab->mat->ctx;
isl_ctx_ref(lp->ctx);
lp->stack = isl_alloc_array(lp->ctx, struct isl_tab_undo *, lp->dim);
lp->row = isl_vec_alloc(lp->ctx, 1 + 2 * lp->dim);
if (!lp->row)
goto error;
- lp->tab = gbr_tab(bset, lp->row);
+ lp->tab = gbr_tab(tab, lp->row);
if (!lp->tab)
goto error;
lp->con_offset = lp->tab->n_con;
enum isl_lp_result res;
unsigned flags = 0;
+ lp->is_fixed = 0;
+
isl_int_set_si(lp->row->el[0], 0);
isl_seq_cpy(lp->row->el + 1, lp->obj, lp->dim);
isl_seq_neg(lp->row->el + 1 + lp->dim, lp->obj, lp->dim);
flags = ISL_TAB_SAVE_DUAL;
res = isl_tab_min(lp->tab, lp->row->el, lp->ctx->one,
&lp->opt, &lp->opt_denom, flags);
+ isl_int_mul_ui(lp->opt_denom, lp->opt_denom, 2);
+ if (isl_int_abs_lt(lp->opt, lp->opt_denom)) {
+ struct isl_vec *sample = isl_tab_get_sample_value(lp->tab);
+ if (!sample)
+ return -1;
+ isl_seq_inner_product(lp->obj, sample->el + 1, lp->dim, &lp->tmp);
+ isl_seq_inner_product(lp->obj, sample->el + 1 + lp->dim, lp->dim, &lp->tmp2);
+ isl_int_cdiv_q(lp->tmp, lp->tmp, sample->el[0]);
+ isl_int_fdiv_q(lp->tmp2, lp->tmp2, sample->el[0]);
+ if (isl_int_ge(lp->tmp, lp->tmp2))
+ lp->is_fixed = 1;
+ isl_vec_free(sample);
+ }
+ isl_int_divexact_ui(lp->opt_denom, lp->opt_denom, 2);
if (res != isl_lp_ok)
return -1;
return 0;
}
+/* The current objective function has a fixed (or no) integer value.
+ * Cut the tableau to the hyperplane that fixes this value in
+ * both halves of the tableau.
+ * Return 1 if the resulting tableau is empty.
+ */
+static int cut_lp_to_hyperplane(struct tab_lp *lp, isl_int *row)
+{
+ enum isl_lp_result res;
+
+ isl_int_set_si(lp->row->el[0], 0);
+ isl_seq_cpy(lp->row->el + 1, row, lp->dim);
+ isl_seq_clr(lp->row->el + 1 + lp->dim, lp->dim);
+ res = isl_tab_min(lp->tab, lp->row->el, lp->ctx->one,
+ &lp->tmp, NULL, 0);
+ if (res != isl_lp_ok)
+ return -1;
+
+ isl_int_neg(lp->row->el[0], lp->tmp);
+ if (isl_tab_add_eq(lp->tab, lp->row->el) < 0)
+ return -1;
+
+ isl_seq_cpy(lp->row->el + 1 + lp->dim, row, lp->dim);
+ isl_seq_clr(lp->row->el + 1, lp->dim);
+ if (isl_tab_add_eq(lp->tab, lp->row->el) < 0)
+ return -1;
+
+ lp->con_offset += 2;
+
+ return lp->tab->empty;
+}
+
static void get_obj_val(struct tab_lp* lp, mpq_t *F)
{
isl_int_neg(mpq_numref(*F), lp->opt);
isl_int_clear(lp->opt);
isl_int_clear(lp->opt_denom);
+ isl_int_clear(lp->tmp);
+ isl_int_clear(lp->tmp2);
isl_vec_free(lp->row);
free(lp->stack);
isl_tab_free(lp->tab);
isl_seq_cpy(lp->row->el + 1, row, lp->dim);
isl_seq_neg(lp->row->el + 1 + lp->dim, row, lp->dim);
- lp->tab = isl_tab_add_valid_eq(lp->tab, lp->row->el);
+ if (isl_tab_add_valid_eq(lp->tab, lp->row->el) < 0)
+ return -1;
return lp->neq++;
}
isl_int_set(mpq_denref(*alpha), lp->tab->dual->el[0]);
}
-static void del_lp_row(struct tab_lp *lp)
+static int del_lp_row(struct tab_lp *lp)
{
lp->neq--;
- isl_tab_rollback(lp->tab, lp->stack[lp->neq]);
+ return isl_tab_rollback(lp->tab, lp->stack[lp->neq]);
}
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