From 5b3080d2d66d27da70fc248d6820541bfed419ce Mon Sep 17 00:00:00 2001
From: Sven Verdoolaege <skimo@kotnet.org>
Date: Mon, 11 Aug 2008 15:15:43 +0200
Subject: [PATCH] isl_basic_set_sample: special case 0D and 1D sets

---
 isl_sample.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)

diff --git a/isl_sample.c b/isl_sample.c
index 2dfaa0a..75514d2 100644
--- a/isl_sample.c
+++ b/isl_sample.c
@@ -5,6 +5,56 @@
 #include "isl_map_private.h"
 #include "isl_equalities.h"
 
+static struct isl_vec *point_sample(struct isl_ctx *ctx,
+	struct isl_basic_set *bset)
+{
+	struct isl_vec *sample;
+	isl_basic_set_free(ctx, bset);
+	sample = isl_vec_alloc(ctx, 1);
+	if (!sample)
+		return NULL;
+	isl_int_set_si(sample->block.data[0], 1);
+	return sample;
+}
+
+static struct isl_vec *interval_sample(struct isl_ctx *ctx,
+	struct isl_basic_set *bset)
+{
+	struct isl_vec *sample;
+
+	bset = isl_basic_set_simplify(ctx, bset);
+	if (!bset)
+		return NULL;
+	if (bset->n_eq > 0)
+		return isl_basic_set_sample(ctx, bset);
+	sample = isl_vec_alloc(ctx, 2);
+	isl_int_set_si(sample->block.data[0], 1);
+	if (bset->n_ineq == 0)
+		isl_int_set_si(sample->block.data[1], 0);
+	else {
+		int i;
+		isl_int t;
+		isl_int_init(t);
+		if (isl_int_is_one(bset->ineq[0][1]))
+			isl_int_neg(sample->block.data[1], bset->ineq[0][0]);
+		else
+			isl_int_set(sample->block.data[1], bset->ineq[0][0]);
+		for (i = 1; i < bset->n_ineq; ++i) {
+			isl_seq_inner_product(sample->block.data,
+						bset->ineq[i], 2, &t);
+			if (isl_int_is_neg(t))
+				break;
+		}
+		isl_int_clear(t);
+		if (i < bset->n_ineq) {
+			isl_vec_free(ctx, sample);
+			sample = isl_vec_alloc(ctx, 0);
+		}
+	}
+	isl_basic_set_free(ctx, bset);
+	return sample;
+}
+
 struct isl_vec *isl_basic_set_sample(struct isl_ctx *ctx,
 	struct isl_basic_set *bset)
 {
@@ -31,6 +81,10 @@ struct isl_vec *isl_basic_set_sample(struct isl_ctx *ctx,
 			isl_mat_free(ctx, T);
 		return sample;
 	}
+	if (bset->dim == 0)
+		return point_sample(ctx, bset);
+	if (bset->dim == 1)
+		return interval_sample(ctx, bset);
 	return isl_pip_basic_set_sample(ctx, bset);
 error:
 	isl_basic_set_free(ctx, bset);
-- 
2.7.4