Viewing file:  isl_scan.c (7.61 KB) -rw-r--r--
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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 <isl_ctx_private.h>
#include <isl_map_private.h>
#include "isl_basis_reduction.h"
#include "isl_scan.h"
#include <isl_seq.h>
#include "isl_tab.h"
#include <isl_val_private.h>
#include <isl_vec_private.h>
struct isl_counter {
struct isl_scan_callback callback;
isl_int count;
isl_int max;
};
static isl_stat increment_counter(struct isl_scan_callback *cb,
__isl_take isl_vec *sample)
{
struct isl_counter *cnt = (struct isl_counter *)cb;
isl_int_add_ui(cnt->count, cnt->count, 1);
isl_vec_free(sample);
if (isl_int_is_zero(cnt->max) || isl_int_lt(cnt->count, cnt->max))
return isl_stat_ok;
return isl_stat_error;
}
static int increment_range(struct isl_scan_callback *cb, isl_int min, isl_int max)
{
struct isl_counter *cnt = (struct isl_counter *)cb;
isl_int_add(cnt->count, cnt->count, max);
isl_int_sub(cnt->count, cnt->count, min);
isl_int_add_ui(cnt->count, cnt->count, 1);
if (isl_int_is_zero(cnt->max) || isl_int_lt(cnt->count, cnt->max))
return 0;
isl_int_set(cnt->count, cnt->max);
return -1;
}
/* Call callback->add with the current sample value of the tableau "tab".
*/
static int add_solution(struct isl_tab *tab, struct isl_scan_callback *callback)
{
struct isl_vec *sample;
if (!tab)
return -1;
sample = isl_tab_get_sample_value(tab);
if (!sample)
return -1;
return callback->add(callback, sample);
}
static isl_stat scan_0D(__isl_take isl_basic_set *bset,
struct isl_scan_callback *callback)
{
struct isl_vec *sample;
sample = isl_vec_alloc(bset->ctx, 1);
isl_basic_set_free(bset);
if (!sample)
return isl_stat_error;
isl_int_set_si(sample->el[0], 1);
return callback->add(callback, sample);
}
/* Look for all integer points in "bset", which is assumed to be bounded,
* and call callback->add on each of them.
*
* We first compute a reduced basis for the set and then scan
* the set in the directions of this basis.
* We basically perform a depth first search, where in each level i
* we compute the range in the i-th basis vector direction, given
* fixed values in the directions of the previous basis vector.
* We then add an equality to the tableau fixing the value in the
* direction of the current basis vector to each value in the range
* in turn and then continue to the next level.
*
* The search is implemented iteratively. "level" identifies the current
* basis vector. "init" is true if we want the first value at the current
* level and false if we want the next value.
* Solutions are added in the leaves of the search tree, i.e., after
* we have fixed a value in each direction of the basis.
*/
isl_stat isl_basic_set_scan(__isl_take isl_basic_set *bset,
struct isl_scan_callback *callback)
{
isl_size dim;
struct isl_mat *B = NULL;
struct isl_tab *tab = NULL;
struct isl_vec *min;
struct isl_vec *max;
struct isl_tab_undo **snap;
int level;
int init;
enum isl_lp_result res;
dim = isl_basic_set_dim(bset, isl_dim_all);
if (dim < 0) {
bset = isl_basic_set_free(bset);
return isl_stat_error;
}
if (dim == 0)
return scan_0D(bset, callback);
min = isl_vec_alloc(bset->ctx, dim);
max = isl_vec_alloc(bset->ctx, dim);
snap = isl_alloc_array(bset->ctx, struct isl_tab_undo *, dim);
if (!min || !max || !snap)
goto error;
tab = isl_tab_from_basic_set(bset, 0);
if (!tab)
goto error;
if (isl_tab_extend_cons(tab, dim + 1) < 0)
goto error;
tab->basis = isl_mat_identity(bset->ctx, 1 + dim);
if (1)
tab = isl_tab_compute_reduced_basis(tab);
if (!tab)
goto error;
B = isl_mat_copy(tab->basis);
if (!B)
goto error;
level = 0;
init = 1;
while (level >= 0) {
int empty = 0;
if (init) {
res = isl_tab_min(tab, B->row[1 + level],
bset->ctx->one, &min->el[level], NULL, 0);
if (res == isl_lp_empty)
empty = 1;
if (res == isl_lp_error || res == isl_lp_unbounded)
goto error;
isl_seq_neg(B->row[1 + level] + 1,
B->row[1 + level] + 1, dim);
res = isl_tab_min(tab, B->row[1 + level],
bset->ctx->one, &max->el[level], NULL, 0);
isl_seq_neg(B->row[1 + level] + 1,
B->row[1 + level] + 1, dim);
isl_int_neg(max->el[level], max->el[level]);
if (res == isl_lp_empty)
empty = 1;
if (res == isl_lp_error || res == isl_lp_unbounded)
goto error;
snap[level] = isl_tab_snap(tab);
} else
isl_int_add_ui(min->el[level], min->el[level], 1);
if (empty || isl_int_gt(min->el[level], max->el[level])) {
level--;
init = 0;
if (level >= 0)
if (isl_tab_rollback(tab, snap[level]) < 0)
goto error;
continue;
}
if (level == dim - 1 && callback->add == increment_counter) {
if (increment_range(callback,
min->el[level], max->el[level]))
goto error;
level--;
init = 0;
if (level >= 0)
if (isl_tab_rollback(tab, snap[level]) < 0)
goto error;
continue;
}
isl_int_neg(B->row[1 + level][0], min->el[level]);
if (isl_tab_add_valid_eq(tab, B->row[1 + level]) < 0)
goto error;
isl_int_set_si(B->row[1 + level][0], 0);
if (level < dim - 1) {
++level;
init = 1;
continue;
}
if (add_solution(tab, callback) < 0)
goto error;
init = 0;
if (isl_tab_rollback(tab, snap[level]) < 0)
goto error;
}
isl_tab_free(tab);
free(snap);
isl_vec_free(min);
isl_vec_free(max);
isl_basic_set_free(bset);
isl_mat_free(B);
return isl_stat_ok;
error:
isl_tab_free(tab);
free(snap);
isl_vec_free(min);
isl_vec_free(max);
isl_basic_set_free(bset);
isl_mat_free(B);
return isl_stat_error;
}
isl_stat isl_set_scan(__isl_take isl_set *set,
struct isl_scan_callback *callback)
{
int i;
if (!set || !callback)
goto error;
set = isl_set_cow(set);
set = isl_set_make_disjoint(set);
set = isl_set_compute_divs(set);
if (!set)
goto error;
for (i = 0; i < set->n; ++i)
if (isl_basic_set_scan(isl_basic_set_copy(set->p[i]),
callback) < 0)
goto error;
isl_set_free(set);
return isl_stat_ok;
error:
isl_set_free(set);
return isl_stat_error;
}
int isl_basic_set_count_upto(__isl_keep isl_basic_set *bset,
isl_int max, isl_int *count)
{
struct isl_counter cnt = { { &increment_counter } };
if (!bset)
return -1;
isl_int_init(cnt.count);
isl_int_init(cnt.max);
isl_int_set_si(cnt.count, 0);
isl_int_set(cnt.max, max);
if (isl_basic_set_scan(isl_basic_set_copy(bset), &cnt.callback) < 0 &&
isl_int_lt(cnt.count, cnt.max))
goto error;
isl_int_set(*count, cnt.count);
isl_int_clear(cnt.max);
isl_int_clear(cnt.count);
return 0;
error:
isl_int_clear(cnt.count);
return -1;
}
int isl_set_count_upto(__isl_keep isl_set *set, isl_int max, isl_int *count)
{
struct isl_counter cnt = { { &increment_counter } };
if (!set)
return -1;
isl_int_init(cnt.count);
isl_int_init(cnt.max);
isl_int_set_si(cnt.count, 0);
isl_int_set(cnt.max, max);
if (isl_set_scan(isl_set_copy(set), &cnt.callback) < 0 &&
isl_int_lt(cnt.count, cnt.max))
goto error;
isl_int_set(*count, cnt.count);
isl_int_clear(cnt.max);
isl_int_clear(cnt.count);
return 0;
error:
isl_int_clear(cnt.count);
return -1;
}
int isl_set_count(__isl_keep isl_set *set, isl_int *count)
{
if (!set)
return -1;
return isl_set_count_upto(set, set->ctx->zero, count);
}
/* Count the total number of elements in "set" (in an inefficient way) and
* return the result.
*/
__isl_give isl_val *isl_set_count_val(__isl_keep isl_set *set)
{
isl_val *v;
if (!set)
return NULL;
v = isl_val_zero(isl_set_get_ctx(set));
v = isl_val_cow(v);
if (!v)
return NULL;
if (isl_set_count(set, &v->n) < 0)
v = isl_val_free(v);
return v;
}
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