add isl_map_is_single_valued

diff --git a/doc/user.pod b/doc/user.pod
index ebbd94f..8925fc0 100644 (file)
--- a/doc/user.pod
+++ b/doc/user.pod
@@ -824,6 +824,10 @@ is already known to be empty.
        int isl_basic_map_is_universe(__isl_keep isl_basic_map *bmap);
        int isl_set_fast_is_universe(__isl_keep isl_set *set);
 
+=item * Single-valuedness
+
+       int isl_map_is_single_valued(__isl_keep isl_map *map);
+
 =back
 
 =head3 Binary Properties

diff --git a/include/isl_map.h b/include/isl_map.h
index caa9983..2e0c3db 100644 (file)
--- a/include/isl_map.h
+++ b/include/isl_map.h
@@ -354,6 +354,7 @@ int isl_map_is_empty(__isl_keep isl_map *map);
 int isl_map_is_subset(__isl_keep isl_map *map1, __isl_keep isl_map *map2);
 int isl_map_is_strict_subset(__isl_keep isl_map *map1, __isl_keep isl_map *map2);
 int isl_map_is_equal(__isl_keep isl_map *map1, __isl_keep isl_map *map2);
+int isl_map_is_single_valued(__isl_keep isl_map *map);
 
 __isl_give isl_map *isl_map_make_disjoint(__isl_take isl_map *map);
 __isl_give isl_map *isl_basic_map_compute_divs(__isl_take isl_basic_map *bmap);

diff --git a/isl_map.c b/isl_map.c
index d221f21..c4c693a 100644 (file)
--- a/isl_map.c
+++ b/isl_map.c
@@ -6709,3 +6709,29 @@ int isl_basic_set_dims_get_sign(__isl_keep isl_basic_set *bset,
        first += pos(bset->dim, type) - 1;
        return isl_basic_set_vars_get_sign(bset, first, n, signs);
 }
+
+/* Check if the given map is single-valued.
+ * We simply compute
+ *
+ *     M \circ M^-1
+ *
+ * and check if the result is a subset of the identity mapping.
+ */
+int isl_map_is_single_valued(__isl_keep isl_map *map)
+{
+       isl_map *test;
+       isl_map *id;
+       int sv;
+
+       test = isl_map_reverse(isl_map_copy(map));
+       test = isl_map_apply_range(test, isl_map_copy(map));
+
+       id = isl_map_identity(isl_dim_range(isl_map_get_dim(map)));
+
+       sv = isl_map_is_subset(test, id);
+
+       isl_map_free(test);
+       isl_map_free(id);
+
+       return sv;
+}

diff --git a/isl_test.c b/isl_test.c
index 0afdc8f..2ea953a 100644 (file)
--- a/isl_test.c
+++ b/isl_test.c
@@ -1259,6 +1259,22 @@ void test_dep(struct isl_ctx *ctx)
        isl_flow_free(flow);
 }
 
+void test_sv(struct isl_ctx *ctx)
+{
+       const char *str;
+       isl_map *map;
+
+       str = "[N] -> { [i] -> [f] : 0 <= i <= N and 0 <= i - 10 f <= 9 }";
+       map = isl_map_read_from_str(ctx, str, -1);
+       assert(isl_map_is_single_valued(map));
+       isl_map_free(map);
+
+       str = "[N] -> { [i] -> [f] : 0 <= i <= N and 0 <= i - 10 f <= 10 }";
+       map = isl_map_read_from_str(ctx, str, -1);
+       assert(!isl_map_is_single_valued(map));
+       isl_map_free(map);
+}
+
 int main()
 {
        struct isl_ctx *ctx;
@@ -1267,6 +1283,7 @@ int main()
        assert(srcdir);
 
        ctx = isl_ctx_alloc();
+       test_sv(ctx);
        test_dep(ctx);
        test_read(ctx);
        test_construction(ctx);