/*
* Copyright 2008-2009 Katholieke Universiteit Leuven
+ * Copyright 2013 Ecole Normale Superieure
*
- * Use of this software is governed by the GNU LGPLv2.1 license
+ * 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
+ * and Ecole Normale Superieure, 45 rue d'Ulm, 75230 Paris, France
*/
-#include "isl_mat.h"
+#include <isl_ctx_private.h>
+#include <isl_mat_private.h>
#include "isl_map_private.h"
#include "isl_tab.h"
-#include "isl_seq.h"
+#include <isl/seq.h>
+#include <isl_config.h>
/*
* The implementation of tableaus in this file was inspired by Section 8
tab->n_div = 0;
tab->n_dead = 0;
tab->n_redundant = 0;
+ tab->strict_redundant = 0;
tab->need_undo = 0;
tab->rational = 0;
tab->empty = 0;
return NULL;
}
+isl_ctx *isl_tab_get_ctx(struct isl_tab *tab)
+{
+ return tab ? isl_mat_get_ctx(tab->mat) : NULL;
+}
+
int isl_tab_extend_cons(struct isl_tab *tab, unsigned n_new)
{
- unsigned off = 2 + tab->M;
+ unsigned off;
if (!tab)
return -1;
+ off = 2 + tab->M;
+
if (tab->max_con < tab->n_con + n_new) {
struct isl_tab_var *con;
return NULL;
}
+static void free_undo_record(struct isl_tab_undo *undo)
+{
+ switch (undo->type) {
+ case isl_tab_undo_saved_basis:
+ free(undo->u.col_var);
+ break;
+ default:;
+ }
+ free(undo);
+}
+
static void free_undo(struct isl_tab *tab)
{
struct isl_tab_undo *undo, *next;
for (undo = tab->top; undo && undo != &tab->bottom; undo = next) {
next = undo->next;
- free(undo);
+ free_undo_record(undo);
}
tab->top = undo;
}
return NULL;
off = 2 + tab->M;
- dup = isl_calloc_type(tab->ctx, struct isl_tab);
+ dup = isl_calloc_type(tab->mat->ctx, struct isl_tab);
if (!dup)
return NULL;
dup->mat = isl_mat_dup(tab->mat);
if (!dup->mat)
goto error;
- dup->var = isl_alloc_array(tab->ctx, struct isl_tab_var, tab->max_var);
+ dup->var = isl_alloc_array(tab->mat->ctx, struct isl_tab_var, tab->max_var);
if (!dup->var)
goto error;
for (i = 0; i < tab->n_var; ++i)
dup->var[i] = tab->var[i];
- dup->con = isl_alloc_array(tab->ctx, struct isl_tab_var, tab->max_con);
+ dup->con = isl_alloc_array(tab->mat->ctx, struct isl_tab_var, tab->max_con);
if (!dup->con)
goto error;
for (i = 0; i < tab->n_con; ++i)
dup->con[i] = tab->con[i];
- dup->col_var = isl_alloc_array(tab->ctx, int, tab->mat->n_col - off);
+ dup->col_var = isl_alloc_array(tab->mat->ctx, int, tab->mat->n_col - off);
if (!dup->col_var)
goto error;
for (i = 0; i < tab->n_col; ++i)
dup->col_var[i] = tab->col_var[i];
- dup->row_var = isl_alloc_array(tab->ctx, int, tab->mat->n_row);
+ dup->row_var = isl_alloc_array(tab->mat->ctx, int, tab->mat->n_row);
if (!dup->row_var)
goto error;
for (i = 0; i < tab->n_row; ++i)
dup->row_var[i] = tab->row_var[i];
if (tab->row_sign) {
- dup->row_sign = isl_alloc_array(tab->ctx, enum isl_tab_row_sign,
+ dup->row_sign = isl_alloc_array(tab->mat->ctx, enum isl_tab_row_sign,
tab->mat->n_row);
if (!dup->row_sign)
goto error;
dup->n_redundant = tab->n_redundant;
dup->rational = tab->rational;
dup->empty = tab->empty;
+ dup->strict_redundant = 0;
dup->need_undo = 0;
dup->in_undo = 0;
dup->M = tab->M;
prod = isl_mat_alloc(mat1->ctx, mat1->n_row + mat2->n_row,
off + col1 + col2);
+ if (!prod)
+ return NULL;
n = 0;
for (i = 0; i < r1; ++i) {
prod->n_redundant = tab1->n_redundant + tab2->n_redundant;
prod->rational = tab1->rational;
prod->empty = tab1->empty || tab2->empty;
+ prod->strict_redundant = tab1->strict_redundant || tab2->strict_redundant;
prod->need_undo = 0;
prod->in_undo = 0;
prod->M = tab1->M;
if (isl_int_is_neg(tab->mat->row[row][1]))
return 0;
+ if (tab->strict_redundant && isl_int_is_zero(tab->mat->row[row][1]))
+ return 0;
if (tab->M && isl_int_is_neg(tab->mat->row[row][2]))
return 0;
static void swap_rows(struct isl_tab *tab, int row1, int row2)
{
int t;
+ enum isl_tab_row_sign s;
+
t = tab->row_var[row1];
tab->row_var[row1] = tab->row_var[row2];
tab->row_var[row2] = t;
if (!tab->row_sign)
return;
- t = tab->row_sign[row1];
+ s = tab->row_sign[row1];
tab->row_sign[row1] = tab->row_sign[row2];
- tab->row_sign[row2] = t;
+ tab->row_sign[row2] = s;
}
static int push_union(struct isl_tab *tab,
{
struct isl_tab_undo *undo;
+ if (!tab)
+ return -1;
if (!tab->need_undo)
return 0;
struct isl_tab_var *var = isl_tab_var_from_row(tab, row);
var->is_redundant = 1;
isl_assert(tab->mat->ctx, row >= tab->n_redundant, return -1);
- if (tab->need_undo || tab->row_var[row] >= 0) {
+ if (tab->preserve || tab->need_undo || tab->row_var[row] >= 0) {
if (tab->row_var[row] >= 0 && !var->is_nonneg) {
var->is_nonneg = 1;
if (isl_tab_push_var(tab, isl_tab_undo_nonneg, var) < 0)
struct isl_tab_var *var;
unsigned off = 2 + tab->M;
+ if (tab->mat->ctx->abort) {
+ isl_ctx_set_error(tab->mat->ctx, isl_error_abort);
+ return -1;
+ }
+
isl_int_swap(mat->row[row][0], mat->row[row][off + col]);
sgn = isl_int_sgn(mat->row[row][0]);
if (sgn < 0) {
return isl_tab_pivot(tab, r, var->index);
}
+/* Check whether all variables that are marked as non-negative
+ * also have a non-negative sample value. This function is not
+ * called from the current code but is useful during debugging.
+ */
+static void check_table(struct isl_tab *tab) __attribute__ ((unused));
static void check_table(struct isl_tab *tab)
{
int i;
if (tab->empty)
return;
- for (i = 0; i < tab->n_row; ++i) {
- if (!isl_tab_var_from_row(tab, i)->is_nonneg)
+ for (i = tab->n_redundant; i < tab->n_row; ++i) {
+ struct isl_tab_var *var;
+ var = isl_tab_var_from_row(tab, i);
+ if (!var->is_nonneg)
continue;
- assert(!isl_int_is_neg(tab->mat->row[i][1]));
+ if (tab->M) {
+ isl_assert(tab->mat->ctx,
+ !isl_int_is_neg(tab->mat->row[i][2]), abort());
+ if (isl_int_is_pos(tab->mat->row[i][2]))
+ continue;
+ }
+ isl_assert(tab->mat->ctx, !isl_int_is_neg(tab->mat->row[i][1]),
+ abort());
}
}
return 1;
}
+int isl_tab_sign_of_max(struct isl_tab *tab, int con)
+{
+ struct isl_tab_var *var;
+
+ if (!tab)
+ return -2;
+
+ var = &tab->con[con];
+ isl_assert(tab->mat->ctx, !var->is_redundant, return -2);
+ isl_assert(tab->mat->ctx, !var->is_zero, return -2);
+
+ return sign_of_max(tab, var);
+}
+
static int row_is_neg(struct isl_tab *tab, int row)
{
if (!tab->M)
* Return 0 otherwise.
*
* The sample value of "var" is assumed to be non-negative when the
- * the function is called and will be made non-negative again before
+ * the function is called. If 1 is returned then the constraint
+ * is not redundant and the sample value is made non-negative again before
* the function returns.
*/
int isl_tab_min_at_most_neg_one(struct isl_tab *tab, struct isl_tab_var *var)
return 0;
do {
find_pivot(tab, var, var, -1, &row, &col);
- if (row == var->index)
+ if (row == var->index) {
+ if (restore_row(tab, var) < -1)
+ return -1;
return 1;
+ }
if (row == -1)
return 0;
pivot_var = var_from_col(tab, col);
}
}
+static int row_is_manifestly_non_integral(struct isl_tab *tab, int row)
+{
+ unsigned off = 2 + tab->M;
+
+ if (tab->M && !isl_int_eq(tab->mat->row[row][2],
+ tab->mat->row[row][0]))
+ return 0;
+ if (isl_seq_first_non_zero(tab->mat->row[row] + off + tab->n_dead,
+ tab->n_col - tab->n_dead) != -1)
+ return 0;
+
+ return !isl_int_is_divisible_by(tab->mat->row[row][1],
+ tab->mat->row[row][0]);
+}
+
+/* For integer tableaus, check if any of the coordinates are stuck
+ * at a non-integral value.
+ */
+static int tab_is_manifestly_empty(struct isl_tab *tab)
+{
+ int i;
+
+ if (tab->empty)
+ return 1;
+ if (tab->rational)
+ return 0;
+
+ for (i = 0; i < tab->n_var; ++i) {
+ if (!tab->var[i].is_row)
+ continue;
+ if (row_is_manifestly_non_integral(tab, tab->var[i].index))
+ return 1;
+ }
+
+ return 0;
+}
+
/* Row variable "var" is non-negative and cannot attain any values
* larger than zero. This means that the coefficients of the unrestricted
* column variables are zero and that the coefficients of the non-negative
if (isl_tab_push_var(tab, isl_tab_undo_zero, var) < 0)
return -1;
for (j = tab->n_dead; j < tab->n_col; ++j) {
+ int recheck;
if (isl_int_is_zero(mat->row[var->index][off + j]))
continue;
isl_assert(tab->mat->ctx,
isl_int_is_neg(mat->row[var->index][off + j]), return -1);
- if (isl_tab_kill_col(tab, j))
+ recheck = isl_tab_kill_col(tab, j);
+ if (recheck < 0)
+ return -1;
+ if (recheck)
--j;
}
if (isl_tab_mark_redundant(tab, var->index) < 0)
return -1;
+ if (tab_is_manifestly_empty(tab) && isl_tab_mark_empty(tab) < 0)
+ return -1;
return 0;
}
* d_r d_r d_r d_x/g m
*
* with g the gcd of d_r and d_x and m the lcm of d_r and d_x.
+ *
+ * If tab->M is set, then, internally, each variable x is represented
+ * as x' - M. We then also need no subtract k d_r from the coefficient of M.
*/
int isl_tab_add_row(struct isl_tab *tab, isl_int *line)
{
isl_int_clear(b);
if (tab->row_sign)
- tab->row_sign[tab->con[r].index] = 0;
+ tab->row_sign[tab->con[r].index] = isl_tab_row_unknown;
return r;
}
/* Add an equality that is known to be valid for the given tableau.
*/
-struct isl_tab *isl_tab_add_valid_eq(struct isl_tab *tab, isl_int *eq)
+int isl_tab_add_valid_eq(struct isl_tab *tab, isl_int *eq)
{
struct isl_tab_var *var;
int r;
if (!tab)
- return NULL;
+ return -1;
r = isl_tab_add_row(tab, eq);
if (r < 0)
- goto error;
+ return -1;
var = &tab->con[r];
r = var->index;
if (row_is_manifestly_zero(tab, r)) {
var->is_zero = 1;
if (isl_tab_mark_redundant(tab, r) < 0)
- goto error;
- return tab;
+ return -1;
+ return 0;
}
if (isl_int_is_neg(tab->mat->row[r][1])) {
}
var->is_nonneg = 1;
if (to_col(tab, var) < 0)
- goto error;
+ return -1;
var->is_nonneg = 0;
if (isl_tab_kill_col(tab, var->index) < 0)
- goto error;
+ return -1;
- return tab;
-error:
- isl_tab_free(tab);
- return NULL;
+ return 0;
}
static int add_zero_row(struct isl_tab *tab)
/* Add equality "eq" and check if it conflicts with the
* previously added constraints or if it is obviously redundant.
*/
-struct isl_tab *isl_tab_add_eq(struct isl_tab *tab, isl_int *eq)
+int isl_tab_add_eq(struct isl_tab *tab, isl_int *eq)
{
struct isl_tab_undo *snap = NULL;
struct isl_tab_var *var;
isl_int cst;
if (!tab)
- return NULL;
- isl_assert(tab->mat->ctx, !tab->M, goto error);
+ return -1;
+ isl_assert(tab->mat->ctx, !tab->M, return -1);
if (tab->need_undo)
snap = isl_tab_snap(tab);
isl_int_clear(cst);
}
if (r < 0)
- goto error;
+ return -1;
var = &tab->con[r];
row = var->index;
if (row_is_manifestly_zero(tab, row)) {
if (snap) {
if (isl_tab_rollback(tab, snap) < 0)
- goto error;
+ return -1;
} else
drop_row(tab, row);
- return tab;
+ return 0;
}
if (tab->bmap) {
tab->bmap = isl_basic_map_add_ineq(tab->bmap, eq);
if (isl_tab_push(tab, isl_tab_undo_bmap_ineq) < 0)
- goto error;
+ return -1;
isl_seq_neg(eq, eq, 1 + tab->n_var);
tab->bmap = isl_basic_map_add_ineq(tab->bmap, eq);
isl_seq_neg(eq, eq, 1 + tab->n_var);
if (isl_tab_push(tab, isl_tab_undo_bmap_ineq) < 0)
- goto error;
+ return -1;
if (!tab->bmap)
- goto error;
+ return -1;
if (add_zero_row(tab) < 0)
- goto error;
+ return -1;
}
sgn = isl_int_sgn(tab->mat->row[row][1]);
if (sgn < 0) {
sgn = sign_of_max(tab, var);
if (sgn < -1)
- goto error;
+ return -1;
if (sgn < 0) {
if (isl_tab_mark_empty(tab) < 0)
- goto error;
- return tab;
+ return -1;
+ return 0;
}
}
var->is_nonneg = 1;
if (to_col(tab, var) < 0)
- goto error;
+ return -1;
var->is_nonneg = 0;
if (isl_tab_kill_col(tab, var->index) < 0)
- goto error;
+ return -1;
- return tab;
-error:
- isl_tab_free(tab);
- return NULL;
+ return 0;
}
/* Construct and return an inequality that expresses an upper bound
return -1;
}
-/* Add an extra div, prescrived by "div" to the tableau and
+/* Check whether the div described by "div" is obviously non-negative.
+ * If we are using a big parameter, then we will encode the div
+ * as div' = M + div, which is always non-negative.
+ * Otherwise, we check whether div is a non-negative affine combination
+ * of non-negative variables.
+ */
+static int div_is_nonneg(struct isl_tab *tab, __isl_keep isl_vec *div)
+{
+ int i;
+
+ if (tab->M)
+ return 1;
+
+ if (isl_int_is_neg(div->el[1]))
+ return 0;
+
+ for (i = 0; i < tab->n_var; ++i) {
+ if (isl_int_is_neg(div->el[2 + i]))
+ return 0;
+ if (isl_int_is_zero(div->el[2 + i]))
+ continue;
+ if (!tab->var[i].is_nonneg)
+ return 0;
+ }
+
+ return 1;
+}
+
+/* Add an extra div, prescribed by "div" to the tableau and
* the associated bmap (which is assumed to be non-NULL).
*
* If add_ineq is not NULL, then this function is used instead
int isl_tab_add_div(struct isl_tab *tab, __isl_keep isl_vec *div,
int (*add_ineq)(void *user, isl_int *), void *user)
{
- int i;
int r;
int k;
int nonneg;
isl_assert(tab->mat->ctx, tab->bmap, return -1);
- for (i = 0; i < tab->n_var; ++i) {
- if (isl_int_is_neg(div->el[2 + i]))
- break;
- if (isl_int_is_zero(div->el[2 + i]))
- continue;
- if (!tab->var[i].is_nonneg)
- break;
- }
- nonneg = i == tab->n_var && !isl_int_is_neg(div->el[1]);
+ nonneg = div_is_nonneg(tab, div);
if (isl_tab_extend_cons(tab, 3) < 0)
return -1;
if (nonneg)
tab->var[r].is_nonneg = 1;
- tab->bmap = isl_basic_map_extend_dim(tab->bmap,
- isl_basic_map_get_dim(tab->bmap), 1, 0, 2);
+ tab->bmap = isl_basic_map_extend_space(tab->bmap,
+ isl_basic_map_get_space(tab->bmap), 1, 0, 2);
k = isl_basic_map_alloc_div(tab->bmap);
if (k < 0)
return -1;
return r;
}
-struct isl_tab *isl_tab_from_basic_map(struct isl_basic_map *bmap)
+/* If "track" is set, then we want to keep track of all constraints in tab
+ * in its bmap field. This field is initialized from a copy of "bmap",
+ * so we need to make sure that all constraints in "bmap" also appear
+ * in the constructed tab.
+ */
+__isl_give struct isl_tab *isl_tab_from_basic_map(
+ __isl_keep isl_basic_map *bmap, int track)
{
int i;
struct isl_tab *tab;
isl_basic_map_total_dim(bmap), 0);
if (!tab)
return NULL;
+ tab->preserve = track;
tab->rational = ISL_F_ISSET(bmap, ISL_BASIC_MAP_RATIONAL);
if (ISL_F_ISSET(bmap, ISL_BASIC_MAP_EMPTY)) {
if (isl_tab_mark_empty(tab) < 0)
goto error;
- return tab;
+ goto done;
}
for (i = 0; i < bmap->n_eq; ++i) {
tab = add_eq(tab, bmap->eq[i]);
if (isl_tab_add_ineq(tab, bmap->ineq[i]) < 0)
goto error;
if (tab->empty)
- return tab;
+ goto done;
}
+done:
+ if (track && isl_tab_track_bmap(tab, isl_basic_map_copy(bmap)) < 0)
+ goto error;
return tab;
error:
isl_tab_free(tab);
return NULL;
}
-struct isl_tab *isl_tab_from_basic_set(struct isl_basic_set *bset)
+__isl_give struct isl_tab *isl_tab_from_basic_set(
+ __isl_keep isl_basic_set *bset, int track)
{
- return isl_tab_from_basic_map((struct isl_basic_map *)bset);
+ return isl_tab_from_basic_map(bset, track);
}
/* Construct a tableau corresponding to the recession cone of "bset".
*/
-struct isl_tab *isl_tab_from_recession_cone(struct isl_basic_set *bset)
+struct isl_tab *isl_tab_from_recession_cone(__isl_keep isl_basic_set *bset,
+ int parametric)
{
isl_int cst;
int i;
struct isl_tab *tab;
+ unsigned offset = 0;
if (!bset)
return NULL;
+ if (parametric)
+ offset = isl_basic_set_dim(bset, isl_dim_param);
tab = isl_tab_alloc(bset->ctx, bset->n_eq + bset->n_ineq,
- isl_basic_set_total_dim(bset), 0);
+ isl_basic_set_total_dim(bset) - offset, 0);
if (!tab)
return NULL;
tab->rational = ISL_F_ISSET(bset, ISL_BASIC_SET_RATIONAL);
isl_int_init(cst);
for (i = 0; i < bset->n_eq; ++i) {
- isl_int_swap(bset->eq[i][0], cst);
- tab = add_eq(tab, bset->eq[i]);
- isl_int_swap(bset->eq[i][0], cst);
+ isl_int_swap(bset->eq[i][offset], cst);
+ if (offset > 0) {
+ if (isl_tab_add_eq(tab, bset->eq[i] + offset) < 0)
+ goto error;
+ } else
+ tab = add_eq(tab, bset->eq[i]);
+ isl_int_swap(bset->eq[i][offset], cst);
if (!tab)
goto done;
}
for (i = 0; i < bset->n_ineq; ++i) {
int r;
- isl_int_swap(bset->ineq[i][0], cst);
- r = isl_tab_add_row(tab, bset->ineq[i]);
- isl_int_swap(bset->ineq[i][0], cst);
+ isl_int_swap(bset->ineq[i][offset], cst);
+ r = isl_tab_add_row(tab, bset->ineq[i] + offset);
+ isl_int_swap(bset->ineq[i][offset], cst);
if (r < 0)
goto error;
tab->con[r].is_nonneg = 1;
* the resulting tableau is empty.
* Otherwise, we know the value will be zero and we close the row.
*/
-static struct isl_tab *cut_to_hyperplane(struct isl_tab *tab,
- struct isl_tab_var *var)
+static int cut_to_hyperplane(struct isl_tab *tab, struct isl_tab_var *var)
{
unsigned r;
isl_int *row;
unsigned off = 2 + tab->M;
if (var->is_zero)
- return tab;
- isl_assert(tab->mat->ctx, !var->is_redundant, goto error);
+ return 0;
+ isl_assert(tab->mat->ctx, !var->is_redundant, return -1);
+ isl_assert(tab->mat->ctx, var->is_nonneg, return -1);
if (isl_tab_extend_cons(tab, 1) < 0)
- goto error;
+ return -1;
r = tab->n_con;
tab->con[r].index = tab->n_row;
tab->n_row++;
tab->n_con++;
if (isl_tab_push_var(tab, isl_tab_undo_allocate, &tab->con[r]) < 0)
- goto error;
+ return -1;
sgn = sign_of_max(tab, &tab->con[r]);
if (sgn < -1)
- goto error;
+ return -1;
if (sgn < 0) {
if (isl_tab_mark_empty(tab) < 0)
- goto error;
- return tab;
+ return -1;
+ return 0;
}
tab->con[r].is_nonneg = 1;
if (isl_tab_push_var(tab, isl_tab_undo_nonneg, &tab->con[r]) < 0)
- goto error;
+ return -1;
/* sgn == 0 */
if (close_row(tab, &tab->con[r]) < 0)
- goto error;
+ return -1;
- return tab;
-error:
- isl_tab_free(tab);
- return NULL;
+ return 0;
}
/* Given a tableau "tab" and an inequality constraint "con" of the tableau,
* If r is a column variable, then we need to modify each row that
* refers to r = r' - 1 by substituting this equality, effectively
* subtracting the coefficient of the column from the constant.
+ * We should only do this if the minimum is manifestly unbounded,
+ * however. Otherwise, we may end up with negative sample values
+ * for non-negative variables.
+ * So, if r is a column variable with a minimum that is not
+ * manifestly unbounded, then we need to move it to a row.
+ * However, the sample value of this row may be negative,
+ * even after the relaxation, so we need to restore it.
+ * We therefore prefer to pivot a column up to a row, if possible.
*/
struct isl_tab *isl_tab_relax(struct isl_tab *tab, int con)
{
var = &tab->con[con];
+ if (var->is_row && (var->index < 0 || var->index < tab->n_redundant))
+ isl_die(tab->mat->ctx, isl_error_invalid,
+ "cannot relax redundant constraint", goto error);
+ if (!var->is_row && (var->index < 0 || var->index < tab->n_dead))
+ isl_die(tab->mat->ctx, isl_error_invalid,
+ "cannot relax dead constraint", goto error);
+
if (!var->is_row && !max_is_manifestly_unbounded(tab, var))
if (to_row(tab, var, 1) < 0)
goto error;
+ if (!var->is_row && !min_is_manifestly_unbounded(tab, var))
+ if (to_row(tab, var, -1) < 0)
+ goto error;
- if (var->is_row)
+ if (var->is_row) {
isl_int_add(tab->mat->row[var->index][1],
tab->mat->row[var->index][1], tab->mat->row[var->index][0]);
- else {
+ if (restore_row(tab, var) < 0)
+ goto error;
+ } else {
int i;
for (i = 0; i < tab->n_row; ++i) {
return NULL;
}
-struct isl_tab *isl_tab_select_facet(struct isl_tab *tab, int con)
+/* Remove the sign constraint from constraint "con".
+ *
+ * If the constraint variable was originally marked non-negative,
+ * then we make sure we mark it non-negative again during rollback.
+ */
+int isl_tab_unrestrict(struct isl_tab *tab, int con)
{
+ struct isl_tab_var *var;
+
if (!tab)
- return NULL;
+ return -1;
+
+ var = &tab->con[con];
+ if (!var->is_nonneg)
+ return 0;
+
+ var->is_nonneg = 0;
+ if (isl_tab_push_var(tab, isl_tab_undo_unrestrict, var) < 0)
+ return -1;
+
+ return 0;
+}
+
+int isl_tab_select_facet(struct isl_tab *tab, int con)
+{
+ if (!tab)
+ return -1;
return cut_to_hyperplane(tab, &tab->con[con]);
}
static int may_be_equality(struct isl_tab *tab, int row)
{
- unsigned off = 2 + tab->M;
- return (tab->rational ? isl_int_is_zero(tab->mat->row[row][1])
- : isl_int_lt(tab->mat->row[row][1],
- tab->mat->row[row][0])) &&
- isl_seq_first_non_zero(tab->mat->row[row] + off + tab->n_dead,
- tab->n_col - tab->n_dead) != -1;
+ return tab->rational ? isl_int_is_zero(tab->mat->row[row][1])
+ : isl_int_lt(tab->mat->row[row][1],
+ tab->mat->row[row][0]);
}
/* Check for (near) equalities among the constraints.
* tableau is integer), then we restrict the value to being zero
* by adding an opposite non-negative variable.
*/
-struct isl_tab *isl_tab_detect_implicit_equalities(struct isl_tab *tab)
+int isl_tab_detect_implicit_equalities(struct isl_tab *tab)
{
int i;
unsigned n_marked;
if (!tab)
- return NULL;
+ return -1;
if (tab->empty)
- return tab;
+ return 0;
if (tab->n_dead == tab->n_col)
- return tab;
+ return 0;
n_marked = 0;
for (i = tab->n_redundant; i < tab->n_row; ++i) {
n_marked--;
sgn = sign_of_max(tab, var);
if (sgn < 0)
- goto error;
+ return -1;
if (sgn == 0) {
if (close_row(tab, var) < 0)
- goto error;
+ return -1;
} else if (!tab->rational && !at_least_one(tab, var)) {
- tab = cut_to_hyperplane(tab, var);
+ if (cut_to_hyperplane(tab, var) < 0)
+ return -1;
return isl_tab_detect_implicit_equalities(tab);
}
for (i = tab->n_redundant; i < tab->n_row; ++i) {
}
}
- return tab;
-error:
- isl_tab_free(tab);
- return NULL;
+ return 0;
+}
+
+/* Update the element of row_var or col_var that corresponds to
+ * constraint tab->con[i] to a move from position "old" to position "i".
+ */
+static int update_con_after_move(struct isl_tab *tab, int i, int old)
+{
+ int *p;
+ int index;
+
+ index = tab->con[i].index;
+ if (index == -1)
+ return 0;
+ p = tab->con[i].is_row ? tab->row_var : tab->col_var;
+ if (p[index] != ~old)
+ isl_die(tab->mat->ctx, isl_error_internal,
+ "broken internal state", return -1);
+ p[index] = ~i;
+
+ return 0;
+}
+
+/* Rotate the "n" constraints starting at "first" to the right,
+ * putting the last constraint in the position of the first constraint.
+ */
+static int rotate_constraints(struct isl_tab *tab, int first, int n)
+{
+ int i, last;
+ struct isl_tab_var var;
+
+ if (n <= 1)
+ return 0;
+
+ last = first + n - 1;
+ var = tab->con[last];
+ for (i = last; i > first; --i) {
+ tab->con[i] = tab->con[i - 1];
+ if (update_con_after_move(tab, i, i - 1) < 0)
+ return -1;
+ }
+ tab->con[first] = var;
+ if (update_con_after_move(tab, first, last) < 0)
+ return -1;
+
+ return 0;
+}
+
+/* Make the equalities that are implicit in "bmap" but that have been
+ * detected in the corresponding "tab" explicit in "bmap" and update
+ * "tab" to reflect the new order of the constraints.
+ *
+ * In particular, if inequality i is an implicit equality then
+ * isl_basic_map_inequality_to_equality will move the inequality
+ * in front of the other equality and it will move the last inequality
+ * in the position of inequality i.
+ * In the tableau, the inequalities of "bmap" are stored after the equalities
+ * and so the original order
+ *
+ * E E E E E A A A I B B B B L
+ *
+ * is changed into
+ *
+ * I E E E E E A A A L B B B B
+ *
+ * where I is the implicit equality, the E are equalities,
+ * the A inequalities before I, the B inequalities after I and
+ * L the last inequality.
+ * We therefore need to rotate to the right two sets of constraints,
+ * those up to and including I and those after I.
+ *
+ * If "tab" contains any constraints that are not in "bmap" then they
+ * appear after those in "bmap" and they should be left untouched.
+ *
+ * Note that this function leaves "bmap" in a temporary state
+ * as it does not call isl_basic_map_gauss. Calling this function
+ * is the responsibility of the caller.
+ */
+__isl_give isl_basic_map *isl_tab_make_equalities_explicit(struct isl_tab *tab,
+ __isl_take isl_basic_map *bmap)
+{
+ int i;
+
+ if (!tab || !bmap)
+ return isl_basic_map_free(bmap);
+ if (tab->empty)
+ return bmap;
+
+ for (i = bmap->n_ineq - 1; i >= 0; --i) {
+ if (!isl_tab_is_equality(tab, bmap->n_eq + i))
+ continue;
+ isl_basic_map_inequality_to_equality(bmap, i);
+ if (rotate_constraints(tab, 0, tab->n_eq + i + 1) < 0)
+ return isl_basic_map_free(bmap);
+ if (rotate_constraints(tab, tab->n_eq + i + 1,
+ bmap->n_ineq - i) < 0)
+ return isl_basic_map_free(bmap);
+ tab->n_eq++;
+ }
+
+ return bmap;
}
static int con_is_redundant(struct isl_tab *tab, struct isl_tab_var *var)
off = 2 + tab->M;
return isl_int_is_zero(tab->mat->row[row][1]) &&
- isl_seq_first_non_zero(tab->mat->row[row] + 2 + tab->n_dead,
+ (!tab->M || isl_int_is_zero(tab->mat->row[row][2])) &&
+ isl_seq_first_non_zero(tab->mat->row[row] + off + tab->n_dead,
tab->n_col - tab->n_dead) == -1;
}
-/* Return the minimial value of the affine expression "f" with denominator
+/* Return the minimal value of the affine expression "f" with denominator
* "denom" in *opt, *opt_denom, assuming the tableau is not empty and
* the expression cannot attain arbitrarily small values.
* If opt_denom is NULL, then *opt is rounded up to the nearest integer.
* The return value reflects the nature of the result (empty, unbounded,
- * minmimal value returned in *opt).
+ * minimal value returned in *opt).
*/
enum isl_lp_result isl_tab_min(struct isl_tab *tab,
isl_int *f, isl_int denom, isl_int *opt, isl_int *opt_denom,
struct isl_tab_var *var;
struct isl_tab_undo *snap;
+ if (!tab)
+ return isl_lp_error;
+
if (tab->empty)
return isl_lp_empty;
if (r < 0)
return isl_lp_error;
var = &tab->con[r];
- isl_int_mul(tab->mat->row[var->index][0],
- tab->mat->row[var->index][0], denom);
for (;;) {
int row, col;
find_pivot(tab, var, var, -1, &row, &col);
if (isl_tab_pivot(tab, row, col) < 0)
return isl_lp_error;
}
+ isl_int_mul(tab->mat->row[var->index][0],
+ tab->mat->row[var->index][0], denom);
if (ISL_FL_ISSET(flags, ISL_TAB_SAVE_DUAL)) {
int i;
if (to_row(tab, var, 1) < 0)
return -1;
- if (var->is_row)
+ if (var->is_row) {
isl_int_sub(tab->mat->row[var->index][1],
tab->mat->row[var->index][1], tab->mat->row[var->index][0]);
- else {
+ if (var->is_nonneg) {
+ int sgn = restore_row(tab, var);
+ isl_assert(tab->mat->ctx, sgn >= 0, return -1);
+ }
+ } else {
int i;
for (i = 0; i < tab->n_row; ++i) {
return 0;
}
+/* Undo the operation performed by isl_tab_unrestrict.
+ *
+ * In particular, mark the variable as being non-negative and make
+ * sure the sample value respects this constraint.
+ */
+static int ununrestrict(struct isl_tab *tab, struct isl_tab_var *var)
+{
+ var->is_nonneg = 1;
+
+ if (var->is_row && restore_row(tab, var) < -1)
+ return -1;
+
+ return 0;
+}
+
static int perform_undo_var(struct isl_tab *tab, struct isl_tab_undo *undo) WARN_UNUSED;
static int perform_undo_var(struct isl_tab *tab, struct isl_tab_undo *undo)
{
struct isl_tab_var *var = var_from_index(tab, undo->u.var_index);
- switch(undo->type) {
+ switch (undo->type) {
case isl_tab_undo_nonneg:
var->is_nonneg = 0;
break;
case isl_tab_undo_redundant:
var->is_redundant = 0;
tab->n_redundant--;
+ restore_row(tab, isl_tab_var_from_row(tab, tab->n_redundant));
break;
case isl_tab_undo_freeze:
var->frozen = 0;
break;
case isl_tab_undo_relax:
return unrelax(tab, var);
+ case isl_tab_undo_unrestrict:
+ return ununrestrict(tab, var);
+ default:
+ isl_die(tab->mat->ctx, isl_error_internal,
+ "perform_undo_var called on invalid undo record",
+ return -1);
}
return 0;
}
free(extra);
- free(col_var);
return 0;
error:
free(extra);
- free(col_var);
return -1;
}
case isl_tab_undo_zero:
case isl_tab_undo_allocate:
case isl_tab_undo_relax:
+ case isl_tab_undo_unrestrict:
return perform_undo_var(tab, undo);
case isl_tab_undo_bmap_eq:
return isl_basic_map_free_equality(tab->bmap, 1);
if (undo == snap)
break;
if (perform_undo(tab, undo) < 0) {
+ tab->top = undo;
free_undo(tab);
tab->in_undo = 0;
return -1;
}
- free(undo);
+ free_undo_record(undo);
}
tab->in_undo = 0;
tab->top = undo;
* In particular, if the row has been reduced to the constant -1,
* then we know the inequality is adjacent (but opposite) to
* an equality in the tableau.
- * If the row has been reduced to r = -1 -r', with r' an inequality
- * of the tableau, then the inequality is adjacent (but opposite)
- * to the inequality r'.
+ * If the row has been reduced to r = c*(-1 -r'), with r' an inequality
+ * of the tableau and c a positive constant, then the inequality
+ * is adjacent (but opposite) to the inequality r'.
*/
static enum isl_ineq_type separation_type(struct isl_tab *tab, unsigned row)
{
if (!isl_int_is_one(tab->mat->row[row][0]))
return isl_ineq_separate;
- if (!isl_int_is_negone(tab->mat->row[row][1]))
- return isl_ineq_separate;
pos = isl_seq_first_non_zero(tab->mat->row[row] + off + tab->n_dead,
tab->n_col - tab->n_dead);
- if (pos == -1)
- return isl_ineq_adj_eq;
+ if (pos == -1) {
+ if (isl_int_is_negone(tab->mat->row[row][1]))
+ return isl_ineq_adj_eq;
+ else
+ return isl_ineq_separate;
+ }
- if (!isl_int_is_negone(tab->mat->row[row][off + tab->n_dead + pos]))
+ if (!isl_int_eq(tab->mat->row[row][1],
+ tab->mat->row[row][off + tab->n_dead + pos]))
return isl_ineq_separate;
pos = isl_seq_first_non_zero(
int isl_tab_track_bmap(struct isl_tab *tab, __isl_take isl_basic_map *bmap)
{
+ bmap = isl_basic_map_cow(bmap);
if (!tab || !bmap)
goto error;
- isl_assert(tab->mat->ctx, tab->n_eq == bmap->n_eq, return -1);
+ if (tab->empty) {
+ bmap = isl_basic_map_set_to_empty(bmap);
+ if (!bmap)
+ goto error;
+ tab->bmap = bmap;
+ return 0;
+ }
+
+ isl_assert(tab->mat->ctx, tab->n_eq == bmap->n_eq, goto error);
isl_assert(tab->mat->ctx,
- tab->n_con == bmap->n_eq + bmap->n_ineq, return -1);
+ tab->n_con == bmap->n_eq + bmap->n_ineq, goto error);
tab->bmap = bmap;
return (isl_basic_set *)tab->bmap;
}
-void isl_tab_dump(struct isl_tab *tab, FILE *out, int indent)
+static void isl_tab_print_internal(__isl_keep struct isl_tab *tab,
+ FILE *out, int indent)
{
unsigned r, c;
int i;
tab->mat->n_row = tab->n_row;
c = tab->mat->n_col;
tab->mat->n_col = 2 + tab->M + tab->n_col;
- isl_mat_dump(tab->mat, out, indent);
+ isl_mat_print_internal(tab->mat, out, indent);
tab->mat->n_row = r;
tab->mat->n_col = c;
if (tab->bmap)
- isl_basic_map_dump(tab->bmap, out, indent);
+ isl_basic_map_print_internal(tab->bmap, out, indent);
+}
+
+void isl_tab_dump(__isl_keep struct isl_tab *tab)
+{
+ isl_tab_print_internal(tab, stderr, 0);
}