mdarray: demo that initializer_list ctor doesn't work

mhoemmen · May 14, 2024 · e4ea3c0 · e4ea3c0
1 parent f648150
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diff --git a/include/experimental/__p1684_bits/mdarray.hpp b/include/experimental/__p1684_bits/mdarray.hpp
@@ -364,6 +364,14 @@ class mdarray {
     static_assert( std::is_constructible<extents_type, OtherExtents>::value, "");
   }
 
+#if 0
+  // Corresponds to deduction guide from std::initializer_list<value_type>
+  MDSPAN_INLINE_FUNCTION
+  constexpr mdarray(std::initializer_list<value_type> values)
+    : map_(extents_type{}), ctr_{values}
+  {}
+#endif // 0
+
   // Corresponds to deduction guide from C array
   MDSPAN_TEMPLATE_REQUIRES(
     class CArray,
@@ -600,5 +608,23 @@ mdarray(CArray& values) -> mdarray<
   decltype(impl::carray_to_array(values))
 >;
 
+#if 0
+// Adding a deduction guide from initializer_list<T> breaks the above
+// C array deduction guide, because construction from
+// initializer_list<T> catches every possible creation of an mdarray
+// from curly braces.
+//
+// We may not know values.size() at compile time,
+// so we have to use a dynamically allocated container.
+template<class T>
+mdarray(std::initializer_list<T> values) ->
+mdarray<
+  std::remove_cvref_t<T>,
+  dextents<std::size_t, 1>,
+  layout_right,
+  std::vector<std::remove_cvref_t<T>>
+>;
+#endif // 0  
+
 } // end namespace MDSPAN_IMPL_PROPOSED_NAMESPACE
 } // end namespace MDSPAN_IMPL_STANDARD_NAMESPACE
diff --git a/tests/test_mdarray_carray_ctad.cpp b/tests/test_mdarray_carray_ctad.cpp
@@ -199,3 +199,39 @@ TEST(TestMdarrayCtorDataCArray, test_mdarray_carray_ctad) {
   __MDSPAN_TESTS_RUN_TEST((test_mdarray_ctad_carray_rank2<float, 3, 4>()))
   __MDSPAN_TESTS_RUN_TEST((test_mdarray_ctad_carray_rank3<float, 3, 4, 5>()))
 }
+
+#if 0
+TEST(TestMdarrayCtorInitializerList, Rank1) {
+  using MDSPAN_IMPL_STANDARD_NAMESPACE::dextents;  
+  using MDSPAN_IMPL_STANDARD_NAMESPACE::extents;
+  using MDSPAN_IMPL_STANDARD_NAMESPACE::layout_right;
+
+  auto error_buffer = allocate_error_buffer();
+  {
+    std::size_t* errors = error_buffer.get();
+    errors[0] = 0;
+    dispatch([errors] _MDSPAN_HOST_DEVICE () {
+      KokkosEx::mdarray m{{1.0f, 2.0f, 3.0f}};
+      static_assert(std::is_same_v<typename decltype(m)::extents_type,
+                    dextents<std::size_t, 1>>);
+      static_assert(std::is_same_v<typename decltype(m)::layout_type,
+                    layout_right>);
+      static_assert(std::is_same_v<typename decltype(m)::container_type,
+                    std::vector<float>>);
+
+      __MDSPAN_DEVICE_ASSERT_EQ(m.rank(), 1);
+      __MDSPAN_DEVICE_ASSERT_EQ(m.rank_dynamic(), 1);
+      __MDSPAN_DEVICE_ASSERT_EQ(m.extent(0), 3);
+
+      for (std::size_t k = 0; k < 3; ++k) {
+#if defined(MDSPAN_USE_BRACKET_OPERATOR) && (MDSPAN_USE_BRACKET_OPERATOR != 0)
+        __MDSPAN_DEVICE_ASSERT_EQ(m[k], (static_cast<float>(k) + 1.0f));
+#else
+        __MDSPAN_DEVICE_ASSERT_EQ(m(k), (static_cast<float>(k) + 1.0f));        
+#endif
+      }
+    });
+    ASSERT_EQ(errors[0], 0);
+  }
+}
+#endif // 0