Skip unit stride consistency check if the dimension size is 1 (#1651)

Fixes GridTools/gt4py#492

include/gridtools/storage/adapter/python_sid_adapter.hpp

@@ -22,7 +22,6 @@
 
 #include <pybind11/pybind11.h>
 
-#include <boost/optional.hpp>
 #include <boost/variant.hpp>
 
 #include "../../common/array.hpp"
@@ -39,11 +38,12 @@ namespace gridtools {
         template <size_t, class>
         struct kind {};
 
-        template <int UnitStrideDim>
+        template <size_t UnitStrideDim>
         struct transform_strides_f {
+            bool m_unit_stride_can_be_used;
             template <size_t I, class T, std::enable_if_t<I == UnitStrideDim, int> = 0>
             integral_constant<pybind11::ssize_t, 1> operator()(T val) const {
-                if (val != 1)
+                if (m_unit_stride_can_be_used && val != 1)
                     throw std::domain_error("incompatible strides, expected unit stride");
                 return {};
             }
@@ -54,7 +54,29 @@ namespace gridtools {
             }
         };
 
-        template <class T, size_t Dim, class Kind, int UnitStrideDim>
+        template <size_t UnitStrideDim,
+            class Strides,
+            class Shape,
+            std::enable_if_t<(UnitStrideDim >= tuple_util::size<std::decay_t<Strides>>::value), int> = 0>
+        Strides &&assign_unit_stride(Strides &&strides, Shape &&) {
+            return std::forward<Strides>(strides);
+        }
+
+        template <size_t UnitStrideDim,
+            class Strides,
+            class Shape,
+            std::enable_if_t<(UnitStrideDim < tuple_util::size<std::decay_t<Strides>>::value), int> = 0>
+        decltype(auto) assign_unit_stride(Strides &&strides, Shape &&shape) {
+            // Numpy may shuffle array layout if the array sizes are equal to one in some dimensions.
+            // In this case the static unit stride calculation doesn't match the actual strides.
+            // Luckily we can ignore that because those strides will not be used (corresponding shape == 1).
+            // See: https://numpy.org/devdocs/release/1.8.0-notes.html#npy-relaxed-strides-checking
+            bool unit_stride_can_be_used = tuple_util::get<UnitStrideDim>(std::forward<Shape>(shape)) > 1;
+            return tuple_util::transform_index(transform_strides_f<UnitStrideDim>{unit_stride_can_be_used},
+                tuple_util::convert_to<tuple>(std::forward<Strides>(strides)));
+        }
+
+        template <class T, size_t Dim, class Kind, size_t UnitStrideDim>
         struct wrapper {
             pybind11::buffer_info m_info;
 
@@ -68,8 +90,7 @@ namespace gridtools {
                     assert(obj.m_info.strides[i] % obj.m_info.itemsize == 0);
                     res[i] = obj.m_info.strides[i] / obj.m_info.itemsize;
                 }
-                return tuple_util::transform_index(
-                    transform_strides_f<UnitStrideDim>{}, tuple_util::convert_to<tuple>(res));
+                return assign_unit_stride<UnitStrideDim>(std::move(res), sid_get_upper_bounds(obj));
             }
 
             friend std::array<integral_constant<pybind11::ssize_t, 0>, Dim> sid_get_lower_bounds(wrapper const &) {
@@ -90,7 +111,7 @@ namespace gridtools {
             }
         };
 
-        template <class T, std::size_t Dim, class Kind = void, int UnitStrideDim = -1>
+        template <class T, std::size_t Dim, class Kind = void, size_t UnitStrideDim = size_t(-1)>
         wrapper<T, Dim, Kind, UnitStrideDim> as_sid(pybind11::buffer const &src) {
             static_assert(
                 std::is_trivially_copyable<T>::value, "as_sid should be instantiated with the trivially copyable type");
@@ -243,7 +264,7 @@ namespace gridtools {
             return res;
         }
 
-        template <class T, size_t Dim, class Kind = void, int UnitStrideDim = -1>
+        template <class T, size_t Dim, class Kind = void, size_t UnitStrideDim = size_t(-1)>
         auto as_cuda_sid(pybind11::object const &src) {
             static_assert(std::is_trivially_copyable<T>::value,
                 "as_cuda_sid should be instantiated with the trivially copyable type");
@@ -320,8 +341,7 @@ namespace gridtools {
             using sid::property;
             return sid::synthetic()
                 .template set<property::origin>(sid::host_device::simple_ptr_holder<T *>{ptr})
-                .template set<property::strides>(tuple_util::transform_index(
-                    transform_strides_f<UnitStrideDim>{}, tuple_util::convert_to<tuple>(strides)))
+                .template set<property::strides>(assign_unit_stride<UnitStrideDim>(std::move(strides), shape))
                 .template set<property::strides_kind, kind<Dim, Kind>>()
                 .template set<property::lower_bounds>(array<integral_constant<size_t, 0>, Dim>())
                 .template set<property::upper_bounds>(shape);