X-Git-Url: http://review.tizen.org/git/?a=blobdiff_plain;f=isl_ilp.c;h=15110c14f014310cbda25d5262e3aac1dbfed491;hb=1515cee3a7f88b136511f2b97d6af3db8e38faad;hp=67e734f37d4254358333bbd3f54b3a10db22d755;hpb=6437c208a0d25a16fbadd23676d66468caa9e8b2;p=platform%2Fupstream%2Fisl.git

diff --git a/isl_ilp.c b/isl_ilp.c
index 67e734f..15110c1 100644
--- a/isl_ilp.c
+++ b/isl_ilp.c
@@ -110,16 +110,10 @@ error:
 	return NULL;
 }
 
-/* Find an integer point in "bset" that minimizes f (if any).
- * If sol_p is not NULL then the integer point is returned in *sol_p.
- * The optimal value of f is returned in *opt.
- *
- * The algorithm maintains a currently best solution and an interval [l, u]
- * of values of f for which integer solutions could potentially still be found.
- * The initial value of the best solution so far is any solution.
- * The initial value of l is minimal value of f over the rationals
- * (rounded up to the nearest integer).
- * The initial value of u is the value of f at the current solution minus 1.
+/* Find an integer point in "bset" that minimizes f (in any) such that
+ * the value of f lies inside the interval [l, u].
+ * Return this integer point if it can be found.
+ * Otherwise, return sol.
  *
  * We perform a number of steps until l > u.
  * In each step, we look for an integer point with value in either
@@ -132,14 +126,72 @@ error:
  * If no point can be found, we update l to the upper bound of the interval
  * we checked (u or l+floor(u-l-1/2)) plus 1.
  */
+static struct isl_vec *solve_ilp_search(struct isl_basic_set *bset,
+	isl_int *f, isl_int *opt, struct isl_vec *sol, isl_int l, isl_int u)
+{
+	isl_int tmp;
+	int divide = 1;
+
+	isl_int_init(tmp);
+
+	while (isl_int_le(l, u)) {
+		struct isl_basic_set *slice;
+		struct isl_vec *sample;
+
+		if (!divide)
+			isl_int_set(tmp, u);
+		else {
+			isl_int_sub(tmp, u, l);
+			isl_int_fdiv_q_ui(tmp, tmp, 2);
+			isl_int_add(tmp, tmp, l);
+		}
+		slice = add_bounds(isl_basic_set_copy(bset), f, l, tmp);
+		sample = isl_basic_set_sample_vec(slice);
+		if (!sample) {
+			isl_vec_free(sol);
+			sol = NULL;
+			break;
+		}
+		if (sample->size > 0) {
+			isl_vec_free(sol);
+			sol = sample;
+			isl_seq_inner_product(f, sol->el, sol->size, opt);
+			isl_int_sub_ui(u, *opt, 1);
+			divide = 1;
+		} else {
+			isl_vec_free(sample);
+			if (!divide)
+				break;
+			isl_int_add_ui(l, tmp, 1);
+			divide = 0;
+		}
+	}
+
+	isl_int_clear(tmp);
+
+	return sol;
+}
+
+/* Find an integer point in "bset" that minimizes f (if any).
+ * If sol_p is not NULL then the integer point is returned in *sol_p.
+ * The optimal value of f is returned in *opt.
+ *
+ * The algorithm maintains a currently best solution and an interval [l, u]
+ * of values of f for which integer solutions could potentially still be found.
+ * The initial value of the best solution so far is any solution.
+ * The initial value of l is minimal value of f over the rationals
+ * (rounded up to the nearest integer).
+ * The initial value of u is the value of f at the initial solution minus 1.
+ *
+ * We then call solve_ilp_search to perform a binary search on the interval.
+ */
 static enum isl_lp_result solve_ilp(struct isl_basic_set *bset,
 				      isl_int *f, isl_int *opt,
 				      struct isl_vec **sol_p)
 {
 	enum isl_lp_result res;
-	isl_int l, u, tmp;
+	isl_int l, u;
 	struct isl_vec *sol;
-	int divide = 1;
 
 	res = isl_basic_set_solve_lp(bset, 0, f, bset->ctx->one,
 					opt, NULL, &sol);
@@ -168,50 +220,18 @@ static enum isl_lp_result solve_ilp(struct isl_basic_set *bset,
 
 	isl_int_init(l);
 	isl_int_init(u);
-	isl_int_init(tmp);
 
 	isl_int_set(l, *opt);
 
 	isl_seq_inner_product(f, sol->el, sol->size, opt);
 	isl_int_sub_ui(u, *opt, 1);
 
-	while (isl_int_le(l, u)) {
-		struct isl_basic_set *slice;
-		struct isl_vec *sample;
-
-		if (!divide)
-			isl_int_set(tmp, u);
-		else {
-			isl_int_sub(tmp, u, l);
-			isl_int_fdiv_q_ui(tmp, tmp, 2);
-			isl_int_add(tmp, tmp, l);
-		}
-		slice = add_bounds(isl_basic_set_copy(bset), f, l, tmp);
-		sample = isl_basic_set_sample_vec(slice);
-		if (!sample) {
-			isl_vec_free(sol);
-			sol = NULL;
-			res = isl_lp_error;
-			break;
-		}
-		if (sample->size > 0) {
-			isl_vec_free(sol);
-			sol = sample;
-			isl_seq_inner_product(f, sol->el, sol->size, opt);
-			isl_int_sub_ui(u, *opt, 1);
-			divide = 1;
-		} else {
-			isl_vec_free(sample);
-			if (!divide)
-				break;
-			isl_int_add_ui(l, tmp, 1);
-			divide = 0;
-		}
-	}
+	sol = solve_ilp_search(bset, f, opt, sol, l, u);
+	if (!sol)
+		res = isl_lp_error;
 
 	isl_int_clear(l);
 	isl_int_clear(u);
-	isl_int_clear(tmp);
 
 	if (sol_p)
 		*sol_p = sol;
@@ -230,6 +250,7 @@ static enum isl_lp_result solve_ilp_with_eq(struct isl_basic_set *bset, int max,
 	struct isl_mat *T = NULL;
 	struct isl_vec *v;
 
+	bset = isl_basic_set_copy(bset);
 	dim = isl_basic_set_total_dim(bset);
 	v = isl_vec_alloc(bset->ctx, 1 + dim);
 	if (!v)
@@ -241,12 +262,13 @@ static enum isl_lp_result solve_ilp_with_eq(struct isl_basic_set *bset, int max,
 		goto error;
 	res = isl_basic_set_solve_ilp(bset, max, v->el, opt, sol_p);
 	isl_vec_free(v);
-	if (res == isl_lp_ok && *sol_p) {
+	if (res == isl_lp_ok && sol_p) {
 		*sol_p = isl_mat_vec_product(T, *sol_p);
 		if (!*sol_p)
 			res = isl_lp_error;
 	} else
 		isl_mat_free(T);
+	isl_basic_set_free(bset);
 	return res;
 error:
 	isl_mat_free(T);