introduced TiledRange::is_congruent

src/TiledArray/tiled_range.h

@@ -423,6 +423,19 @@ inline bool operator==(const TiledRange& r1, const TiledRange& r2) {
          std::equal(r1.data().begin(), r1.data().end(), r2.data().begin());
 }
 
+/// Test that two TiledRange objects are congruent
+
+/// Two tranges are congruent if one is a translation of another (i.e. their
+/// ranks and extents of all tiles) agree \param r1 a TiledRange object \param
+/// r2 a TiledRange object
+inline bool is_congruent(const TiledRange& r1, const TiledRange& r2) {
+  return r1.rank() == r2.rank() &&
+         std::equal(r1.begin(), r1.end(), r2.begin(),
+                    [](const auto& tr1_1, const auto& tr1_2) {
+                      return is_congruent(tr1_1, tr1_2);
+                    });
+}
+
 inline bool operator!=(const TiledRange& r1, const TiledRange& r2) {
   return !operator==(r1, r2);
 }

tests/tiled_range.cpp

@@ -119,13 +119,26 @@ BOOST_AUTO_TEST_CASE(comparison) {
   TiledRange r1{{0, 2, 4, 6, 8, 10}, {0, 2, 4, 6, 8, 10}};
   TiledRange r2{{0, 2, 4, 6, 8, 10}, {0, 2, 4, 6, 8, 10}};
   TiledRange r3{{0, 3, 6, 9, 12, 15}, {0, 3, 6, 9, 12, 15}};
+  BOOST_CHECK(r1 == r1);     // self-comparison
   BOOST_CHECK(r1 == r2);     // check equality operator
   BOOST_CHECK(!(r1 != r2));  // check not-equal operator
   BOOST_CHECK(
       !(r1 == r3));  // check for inequality with different number of tiles.
   BOOST_CHECK(r1 != r3);
 }
 
+BOOST_AUTO_TEST_CASE(congruency) {
+  TiledRange r1{{0, 2, 4, 6, 8, 10}, {0, 2, 4, 6, 8, 10}};
+  TiledRange r2{{1, 3, 5, 7, 9, 11}, {2, 4, 6, 8, 10, 12}};
+  TiledRange r3{{0, 3, 6, 9, 12, 15}, {0, 3, 6, 9, 12, 15}};
+  BOOST_CHECK(r1 == r1 && is_congruent(r1, r1));  // congruent with self
+  BOOST_CHECK(r1 != r2 &&
+              is_congruent(r1, r2));  // r1 and r2 are not equal but congruent
+  BOOST_CHECK(
+      r1 != r3 &&
+      !is_congruent(r1, r3));  // r1 and r3 are not equal and not congruent
+}
+
 BOOST_AUTO_TEST_CASE(assignment) {
   TiledRange r1;