}
tab->n_row = 0;
tab->n_con = 0;
+ tab->n_eq = 0;
tab->max_con = n_row;
tab->n_col = n_var;
tab->n_var = n_var;
tab->need_undo = 0;
tab->rational = 0;
tab->empty = 0;
+ tab->in_undo = 0;
tab->bottom.type = isl_tab_undo_bottom;
tab->bottom.next = NULL;
tab->top = &tab->bottom;
return;
free_undo(ctx, tab);
isl_mat_free(ctx, tab->mat);
+ isl_vec_free(tab->dual);
free(tab->var);
free(tab->con);
free(tab->row_var);
/* Find a pivot (row and col) that will increase (sgn > 0) or decrease
* (sgn < 0) the value of row variable var.
+ * If not NULL, then skip_var is a row variable that should be ignored
+ * while looking for a pivot row. It is usually equal to var.
+ *
* As the given row in the tableau is of the form
*
* x_r = a_r0 + \sum_i a_ri x_i
* opposite direction.
*/
static void find_pivot(struct isl_ctx *ctx, struct isl_tab *tab,
- struct isl_tab_var *var, int sgn, int *row, int *col)
+ struct isl_tab_var *var, struct isl_tab_var *skip_var,
+ int sgn, int *row, int *col)
{
int j, r, c;
isl_int *tr;
return;
sgn *= isl_int_sgn(tr[2 + c]);
- r = pivot_row(ctx, tab, var, sgn, c);
+ r = pivot_row(ctx, tab, skip_var, sgn, c);
*row = r < 0 ? var->index : r;
*col = c;
}
var = var_from_col(ctx, tab, col);
var->is_row = 0;
var->index = col;
+ if (tab->in_undo)
+ return;
for (i = tab->n_redundant; i < tab->n_row; ++i) {
if (isl_int_is_zero(mat->row[i][2 + col]))
continue;
return 1;
to_row(ctx, tab, var, 1);
while (!isl_int_is_pos(tab->mat->row[var->index][1])) {
- find_pivot(ctx, tab, var, 1, &row, &col);
+ find_pivot(ctx, tab, var, var, 1, &row, &col);
if (row == -1)
return isl_int_sgn(tab->mat->row[var->index][1]);
pivot(ctx, tab, row, col);
int row, col;
while (isl_int_is_neg(tab->mat->row[var->index][1])) {
- find_pivot(ctx, tab, var, 1, &row, &col);
+ find_pivot(ctx, tab, var, var, 1, &row, &col);
if (row == -1)
break;
pivot(ctx, tab, row, col);
int row, col;
while (isl_int_is_neg(tab->mat->row[var->index][1])) {
- find_pivot(ctx, tab, var, 1, &row, &col);
+ find_pivot(ctx, tab, var, var, 1, &row, &col);
if (row == -1)
break;
if (row == var->index) /* manifestly unbounded */
if (var->is_redundant)
return 0;
while (!isl_int_is_neg(tab->mat->row[var->index][1])) {
- find_pivot(ctx, tab, var, -1, &row, &col);
+ find_pivot(ctx, tab, var, var, -1, &row, &col);
if (row == var->index)
return -1;
if (row == -1)
if (var->is_redundant)
return 0;
do {
- find_pivot(ctx, tab, var, -1, &row, &col);
+ find_pivot(ctx, tab, var, var, -1, &row, &col);
if (row == var->index)
return 1;
if (row == -1)
to_row(ctx, tab, var, 1);
r = tab->mat->row[var->index];
while (isl_int_lt(r[1], r[0])) {
- find_pivot(ctx, tab, var, 1, &row, &col);
+ find_pivot(ctx, tab, var, var, 1, &row, &col);
if (row == -1)
return isl_int_ge(r[1], r[0]);
if (row == var->index) /* manifestly unbounded */
return NULL;
}
+/* Pivot a non-negative variable down until it reaches the value zero
+ * and then pivot the variable into a column position.
+ */
+static int to_col(struct isl_ctx *ctx,
+ struct isl_tab *tab, struct isl_tab_var *var)
+{
+ int i;
+ int row, col;
+
+ if (!var->is_row)
+ return;
+
+ while (isl_int_is_pos(tab->mat->row[var->index][1])) {
+ find_pivot(ctx, tab, var, NULL, -1, &row, &col);
+ isl_assert(ctx, row != -1, return -1);
+ pivot(ctx, tab, row, col);
+ if (!var->is_row)
+ return;
+ }
+
+ for (i = tab->n_dead; i < tab->n_col; ++i)
+ if (!isl_int_is_zero(tab->mat->row[var->index][2 + i]))
+ break;
+
+ isl_assert(ctx, i < tab->n_col, return -1);
+ pivot(ctx, tab, var->index, i);
+
+ return 0;
+}
+
/* We assume Gaussian elimination has been performed on the equalities.
* The equalities can therefore never conflict.
* Adding the equalities is currently only really useful for a later call
kill_col(ctx, tab, i);
break;
}
+ tab->n_eq++;
+
+ return tab;
+error:
+ isl_tab_free(ctx, tab);
+ return NULL;
+}
+
+/* Add an equality that is known to be valid for the given tableau.
+ */
+struct isl_tab *isl_tab_add_valid_eq(struct isl_ctx *ctx,
+ struct isl_tab *tab, isl_int *eq)
+{
+ struct isl_tab_var *var;
+ int i;
+ int r;
+
+ if (!tab)
+ return NULL;
+ r = add_row(ctx, tab, eq);
+ if (r < 0)
+ goto error;
+
+ var = &tab->con[r];
+ r = var->index;
+ if (isl_int_is_neg(tab->mat->row[r][1]))
+ isl_seq_neg(tab->mat->row[r] + 1, tab->mat->row[r] + 1,
+ 1 + tab->n_col);
+ var->is_nonneg = 1;
+ if (to_col(ctx, tab, var) < 0)
+ goto error;
+ var->is_nonneg = 0;
+ kill_col(ctx, tab, var->index);
return tab;
error:
return vec;
}
+struct isl_vec *isl_tab_get_sample_value(struct isl_ctx *ctx,
+ struct isl_tab *tab)
+{
+ int i;
+ struct isl_vec *vec;
+ isl_int m;
+
+ if (!tab)
+ return NULL;
+
+ vec = isl_vec_alloc(ctx, 1 + tab->n_var);
+ if (!vec)
+ return NULL;
+
+ isl_int_init(m);
+
+ isl_int_set_si(vec->block.data[0], 1);
+ for (i = 0; i < tab->n_var; ++i) {
+ int row;
+ if (!tab->var[i].is_row) {
+ isl_int_set_si(vec->block.data[1 + i], 0);
+ continue;
+ }
+ row = tab->var[i].index;
+ isl_int_gcd(m, vec->block.data[0], tab->mat->row[row][0]);
+ isl_int_divexact(m, tab->mat->row[row][0], m);
+ isl_seq_scale(vec->block.data, vec->block.data, m, 1 + i);
+ isl_int_divexact(m, vec->block.data[0], tab->mat->row[row][0]);
+ isl_int_mul(vec->block.data[1 + i], m, tab->mat->row[row][1]);
+ }
+ isl_seq_normalize(vec->block.data, vec->size);
+
+ isl_int_clear(m);
+ return vec;
+}
+
/* Update "bmap" based on the results of the tableau "tab".
* In particular, implicit equalities are made explicit, redundant constraints
* are removed and if the sample value happens to be integer, it is stored
if (!tab)
return bmap;
- n_eq = bmap->n_eq;
+ n_eq = tab->n_eq;
if (tab->empty)
bmap = isl_basic_map_set_to_empty(bmap);
else
* minmimal value returned in *opt).
*/
enum isl_lp_result isl_tab_min(struct isl_ctx *ctx, struct isl_tab *tab,
- isl_int *f, isl_int denom, isl_int *opt, isl_int *opt_denom)
+ isl_int *f, isl_int denom, isl_int *opt, isl_int *opt_denom,
+ unsigned flags)
{
int r;
enum isl_lp_result res = isl_lp_ok;
struct isl_tab_var *var;
+ struct isl_tab_undo *snap;
if (tab->empty)
return isl_lp_empty;
+ snap = isl_tab_snap(ctx, tab);
r = add_row(ctx, tab, f);
if (r < 0)
return isl_lp_error;
tab->mat->row[var->index][0], denom);
for (;;) {
int row, col;
- find_pivot(ctx, tab, var, -1, &row, &col);
+ find_pivot(ctx, tab, var, var, -1, &row, &col);
if (row == var->index) {
res = isl_lp_unbounded;
break;
break;
pivot(ctx, tab, row, col);
}
- if (drop_row(ctx, tab, var->index) < 0)
+ if (isl_tab_rollback(ctx, tab, snap) < 0)
return isl_lp_error;
+ if (ISL_FL_ISSET(flags, ISL_TAB_SAVE_DUAL)) {
+ int i;
+
+ isl_vec_free(tab->dual);
+ tab->dual = isl_vec_alloc(ctx, 1 + tab->n_con);
+ if (!tab->dual)
+ return isl_lp_error;
+ isl_int_set(tab->dual->el[0], tab->mat->row[var->index][0]);
+ for (i = 0; i < tab->n_con; ++i) {
+ if (tab->con[i].is_row)
+ isl_int_set_si(tab->dual->el[1 + i], 0);
+ else {
+ int pos = 2 + tab->con[i].index;
+ isl_int_set(tab->dual->el[1 + i],
+ tab->mat->row[var->index][pos]);
+ }
+ }
+ }
if (res == isl_lp_ok) {
if (opt_denom) {
isl_int_set(*opt, tab->mat->row[var->index][1]);
if (!tab)
return -1;
+ tab->in_undo = 1;
for (undo = tab->top; undo && undo != &tab->bottom; undo = next) {
next = undo->next;
if (undo == snap)
perform_undo(ctx, tab, undo);
free(undo);
}
+ tab->in_undo = 0;
tab->top = undo;
if (!undo)
return -1;
/* Check the effect of inequality "ineq" on the tableau "tab".
* The result may be
* isl_ineq_redundant: satisfied by all points in the tableau
- * isl_ineq_separate: satisfied by no point in tha tableau
+ * isl_ineq_separate: satisfied by no point in the tableau
* isl_ineq_cut: satisfied by some by not all points
* isl_ineq_adj_eq: adjacent to an equality
* isl_ineq_adj_ineq: adjacent to an inequality.
projects / platform / upstream / isl.git / blobdiff