X-Git-Url: http://review.tizen.org/git/?a=blobdiff_plain;f=isl_tab.c;h=4f2e783503d7f38e1409fc336c66c61b4f367886;hb=edb02fef62bd0f8bf73586b95a02b8cf34366d7a;hp=b3e561819d9cdbe27647862a4c5e0a51e5680765;hpb=533f7c20648f85eba1652d046507cbfd340ce436;p=platform%2Fupstream%2Fisl.git

diff --git a/isl_tab.c b/isl_tab.c
index b3e5618..4f2e783 100644
--- a/isl_tab.c
+++ b/isl_tab.c
@@ -42,6 +42,7 @@ struct isl_tab *isl_tab_alloc(struct isl_ctx *ctx,
 	}
 	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;
@@ -50,6 +51,7 @@ struct isl_tab *isl_tab_alloc(struct isl_ctx *ctx,
 	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;
@@ -114,6 +116,7 @@ void isl_tab_free(struct isl_ctx *ctx, struct isl_tab *tab)
 		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);
@@ -234,6 +237,9 @@ static int pivot_row(struct isl_ctx *ctx, struct isl_tab *tab,
 
 /* 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
@@ -246,7 +252,8 @@ static int pivot_row(struct isl_ctx *ctx, struct isl_tab *tab,
  * 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;
@@ -270,7 +277,7 @@ static void find_pivot(struct isl_ctx *ctx, struct isl_tab *tab,
 		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;
 }
@@ -478,6 +485,8 @@ static void pivot(struct isl_ctx *ctx,
 	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;
@@ -538,7 +547,7 @@ static int sign_of_max(struct isl_ctx *ctx,
 		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);
@@ -559,7 +568,7 @@ static int restore_row(struct isl_ctx *ctx,
 	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);
@@ -580,7 +589,7 @@ static int at_least_zero(struct isl_ctx *ctx,
 	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 */
@@ -636,7 +645,7 @@ static int sign_of_min(struct isl_ctx *ctx,
 	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)
@@ -694,7 +703,7 @@ static int min_at_most_neg_one(struct isl_ctx *ctx,
 	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)
@@ -729,7 +738,7 @@ static int at_least_one(struct isl_ctx *ctx,
 	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 */
@@ -919,6 +928,36 @@ error:
 	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
@@ -944,6 +983,39 @@ static struct isl_tab *add_eq(struct isl_ctx *ctx,
 		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:
@@ -1098,6 +1170,42 @@ static struct isl_vec *extract_integer_sample(struct isl_ctx *ctx,
 	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
@@ -1117,7 +1225,7 @@ struct isl_basic_map *isl_basic_map_update_from_tab(struct isl_basic_map *bmap,
 	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
@@ -1443,15 +1551,18 @@ int isl_tab_is_equality(struct isl_ctx *ctx, struct isl_tab *tab, int con)
  * 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;
@@ -1460,7 +1571,7 @@ enum isl_lp_result isl_tab_min(struct isl_ctx *ctx, struct isl_tab *tab,
 		    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;
@@ -1469,8 +1580,26 @@ enum isl_lp_result isl_tab_min(struct isl_ctx *ctx, struct isl_tab *tab,
 			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]);
@@ -1575,6 +1704,7 @@ int isl_tab_rollback(struct isl_ctx *ctx, struct isl_tab *tab,
 	if (!tab)
 		return -1;
 
+	tab->in_undo = 1;
 	for (undo = tab->top; undo && undo != &tab->bottom; undo = next) {
 		next = undo->next;
 		if (undo == snap)
@@ -1582,6 +1712,7 @@ int isl_tab_rollback(struct isl_ctx *ctx, struct isl_tab *tab,
 		perform_undo(ctx, tab, undo);
 		free(undo);
 	}
+	tab->in_undo = 0;
 	tab->top = undo;
 	if (!undo)
 		return -1;
@@ -1629,7 +1760,7 @@ static enum isl_ineq_type separation_type(struct isl_ctx *ctx,
 /* 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.