From 10aa3b971daf48c941794844fa1187d00b5b68d1 Mon Sep 17 00:00:00 2001
From: Sven Verdoolaege <skimo@kotnet.org>
Date: Mon, 16 Apr 2012 17:27:00 +0200
Subject: [PATCH] add isl_multi_aff_identity

Signed-off-by: Sven Verdoolaege <skimo@kotnet.org>
---
 doc/user.pod      |  2 ++
 include/isl/aff.h |  1 +
 isl_aff.c         | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 54 insertions(+)

diff --git a/doc/user.pod b/doc/user.pod
index d07cef9..1f5e0b4 100644
--- a/doc/user.pod
+++ b/doc/user.pod
@@ -3354,6 +3354,8 @@ can be created using the following functions.
 		__isl_take isl_space *space);
 	__isl_give isl_multi_aff *isl_multi_aff_zero(
 		__isl_take isl_space *space);
+	__isl_give isl_multi_aff *isl_multi_aff_identity(
+		__isl_take isl_space *space);
 	__isl_give isl_pw_multi_aff *
 	isl_pw_multi_aff_from_multi_aff(
 		__isl_take isl_multi_aff *ma);
diff --git a/include/isl/aff.h b/include/isl/aff.h
index faeb957..b4a2808 100644
--- a/include/isl/aff.h
+++ b/include/isl/aff.h
@@ -248,6 +248,7 @@ __isl_give isl_set *isl_pw_aff_list_gt_set(__isl_take isl_pw_aff_list *list1,
 	__isl_take isl_pw_aff_list *list2);
 
 __isl_give isl_multi_aff *isl_multi_aff_zero(__isl_take isl_space *space);
+__isl_give isl_multi_aff *isl_multi_aff_identity(__isl_take isl_space *space);
 
 isl_ctx *isl_multi_aff_get_ctx(__isl_keep isl_multi_aff *maff);
 __isl_give isl_space *isl_multi_aff_get_space(__isl_keep isl_multi_aff *maff);
diff --git a/isl_aff.c b/isl_aff.c
index 85e4953..b29d29f 100644
--- a/isl_aff.c
+++ b/isl_aff.c
@@ -2173,6 +2173,57 @@ __isl_give isl_multi_aff *isl_multi_aff_zero(__isl_take isl_space *space)
 	return ma;
 }
 
+/* Create an isl_multi_aff in the given space that maps each
+ * input dimension to the corresponding output dimension.
+ */
+__isl_give isl_multi_aff *isl_multi_aff_identity(__isl_take isl_space *space)
+{
+	int n;
+	isl_multi_aff *ma;
+
+	if (!space)
+		return NULL;
+
+	if (isl_space_is_set(space))
+		isl_die(isl_space_get_ctx(space), isl_error_invalid,
+			"expecting map space", goto error);
+
+	n = isl_space_dim(space, isl_dim_out);
+	if (n != isl_space_dim(space, isl_dim_in))
+		isl_die(isl_space_get_ctx(space), isl_error_invalid,
+			"number of input and output dimensions needs to be "
+			"the same", goto error);
+
+	ma = isl_multi_aff_alloc(isl_space_copy(space));
+
+	if (!n)
+		isl_space_free(space);
+	else {
+		int i;
+		isl_local_space *ls;
+		isl_aff *aff;
+
+		space = isl_space_domain(space);
+		ls = isl_local_space_from_space(space);
+		aff = isl_aff_zero_on_domain(ls);
+
+		for (i = 0; i < n; ++i) {
+			isl_aff *aff_i;
+			aff_i = isl_aff_copy(aff);
+			aff_i = isl_aff_add_coefficient_si(aff_i,
+							    isl_dim_in, i, 1);
+			ma = isl_multi_aff_set_aff(ma, i, aff_i);
+		}
+
+		isl_aff_free(aff);
+	}
+
+	return ma;
+error:
+	isl_space_free(space);
+	return NULL;
+}
+
 /* Create an isl_pw_multi_aff with the given isl_multi_aff on a universe
  * domain.
  */
-- 
2.7.4