Bug fix for reversing OrderedGroups.
Reverse() method now handles the case where no groups exist.
Change-Id: Ia1ef08aa3cde01ceb71285b605a2e1f882c3b620
diff --git a/include/ceres/ordered_groups.h b/include/ceres/ordered_groups.h
index 74a3995..aa1bd3a 100644
--- a/include/ceres/ordered_groups.h
+++ b/include/ceres/ordered_groups.h
@@ -122,6 +122,10 @@
// Reverse the order of the groups in place.
void Reverse() {
+ if (NumGroups() == 0) {
+ return;
+ }
+
typename std::map<int, std::set<T> >::reverse_iterator it =
group_to_elements_.rbegin();
std::map<int, std::set<T> > new_group_to_elements;
diff --git a/internal/ceres/ordered_groups_test.cc b/internal/ceres/ordered_groups_test.cc
index 5c2e3ec..4510686 100644
--- a/internal/ceres/ordered_groups_test.cc
+++ b/internal/ceres/ordered_groups_test.cc
@@ -159,6 +159,20 @@
EXPECT_EQ(ordering.GroupId(x + 2), 2);
}
+TEST(OrderedGroups, ReverseOrderingWithEmptyOrderedGroups) {
+ ParameterBlockOrdering ordering;
+ // This should be a no-op.
+ ordering.Reverse();
+
+ // Ensure the properties of an empty OrderedGroups still hold after Reverse().
+ EXPECT_EQ(ordering.NumGroups(), 0);
+ EXPECT_EQ(ordering.NumElements(), 0);
+ EXPECT_EQ(ordering.GroupSize(1), 0);
+ double x;
+ EXPECT_EQ(ordering.GroupId(&x), -1);
+ EXPECT_FALSE(ordering.Remove(&x));
+}
+
TEST(OrderedGroups, BulkRemove) {
ParameterBlockOrdering ordering;
double x[3];
