Reshape method

examples/CMakeLists.txt

@@ -3,6 +3,10 @@
 # SPDX-License-Identifier: (BSD-3-Clause)
 ###############################################################################
 
+raja_add_executable(
+  NAME reshape
+  SOURCES reshape.cpp)
+
 raja_add_executable(
   NAME tut_launch_basic
   SOURCES tut_launch_basic.cpp)

examples/reshape.cpp

@@ -0,0 +1,163 @@
+//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~//
+// Copyright (c) 2016-24, Lawrence Livermore National Security, LLC
+// and RAJA project contributors. See the RAJA/LICENSE file for details.
+//
+// SPDX-License-Identifier: (BSD-3-Clause)
+//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~//
+
+#include <cmath>
+#include <cstdlib>
+#include <cstring>
+#include <iostream>
+
+#include "RAJA/RAJA.hpp"
+#include "RAJA/util/Timer.hpp"
+
+
+#include "memoryManager.hpp"
+
+/*
+ *  RAJA Reshape method
+ *
+ *  This example will intialize array using
+ *  the RAJA Reshape method. The Reshape
+ *  method offers right and left most unit
+ *  stride.
+ *
+ */
+
+/*
+ * Define number of threads in a GPU thread block
+ */
+#if defined(RAJA_ENABLE_CUDA)
+constexpr int CUDA_BLOCK_SIZE = 256;
+#endif
+
+#if defined(RAJA_ENABLE_HIP)
+constexpr int HIP_BLOCK_SIZE = 256;
+#endif
+
+//
+//Function for checking results
+//
+void checkResult(int *ptr, int K, int N, int M);
+
+int main(int RAJA_UNUSED_ARG(argc), char **RAJA_UNUSED_ARG(argv[]))
+{
+
+  std::cout << "\n\nRAJA reshape method example....\n"<< std::endl;
+
+  const int K = 3;
+  const int N = 1;
+  const int M = 2;
+
+  // Allocate memory for pointer
+  int *Rptr = memoryManager::allocate<int>(K * N * M);
+  int *Lptr = memoryManager::allocate<int>(K * N * M);
+  int *Cptr = memoryManager::allocate<int>(K * N * M);
+
+//----------------------------------------------------------------------------//
+//
+// Initialize memory using right most unit stride
+//
+//----------------------------------------------------------------------------//
+  std::cout << "\n\nInitialize array with right most indexing...\n";
+  auto Rview = RAJA::Reshape<RAJA::layout_right>::get(Rptr, K, N, M);
+
+  for(int k = 0; k < K; ++k) {
+    for(int n = 0; n < N; ++n) {
+      for(int m = 0; m < M; ++m) {
+        const int idx = m + M * (n + N * k);
+        Rview(k,n,m) = idx;
+      }
+    }
+  }
+
+  checkResult(Rptr, K, N, M);
+
+
+//----------------------------------------------------------------------------//
+//
+// Initialize memory using left most unit stride
+//
+//----------------------------------------------------------------------------//
+  std::cout << "\n\nInitialize array with left most indexing...\n";
+
+  auto Lview = RAJA::Reshape<RAJA::layout_left>::get(Lptr, K, N, M);
+
+  //Note the loop ordering has change from above
+  for(int m = 0; m < M; ++m) {
+    for(int n = 0; n < N; ++n) {
+      for(int k = 0; k < K; ++k) {
+
+        const int idx = k + K * (n + N * m);
+        Lview(k,n,m) = idx;
+      }
+    }
+  }
+
+  checkResult(Lptr, K, N, M);
+
+
+//----------------------------------------------------------------------------//
+//
+// Initialize memory using custom ordering, longest stride starts at the left,
+// right most is assumed to have unit stride.
+//
+//----------------------------------------------------------------------------//
+  std::cout << "\n\nInitialize array with custom indexing...\n";
+
+  using custom_seq = std::index_sequence<2U,0U,1U>;
+
+
+  auto Cview = RAJA::Reshape<custom_seq>::get(Cptr, K, N, M);
+
+  //Note the loop ordering has change from above
+  for(int m = 0; m < M; ++m) {
+    for(int k = 0; k < K; ++k) {
+      for(int n = 0; n < N; ++n) {
+
+        const int idx = n + N * (k + K * m);
+        Cview(k,n,m) = idx;
+      }
+    }
+  }
+
+  checkResult(Cptr, K, N, M);
+
+
+//
+// Clean up.
+//
+  memoryManager::deallocate(Rptr);
+  memoryManager::deallocate(Lptr);
+
+  std::cout << "\n DONE!...\n";
+  return 0;
+}
+
+//
+// check result
+//
+void checkResult(int *ptr, int K, int N, int M)
+{
+
+  bool status = true;
+
+  for(int k = 0; k < K; ++k) {
+    for(int n = 0; n < N; ++n) {
+      for(int m = 0; m < M; ++m) {
+        const int idx = m + M * (n + N * k);
+        if (ptr[idx] != idx) {
+          status = false;
+        }
+      }
+    }
+  }
+
+  if ( status ) {
+    std::cout << "\tresult -- PASS\n";
+  } else {
+    std::cout << "\tresult -- FAIL\n";
+  }
+}

include/RAJA/util/View.hpp

@@ -18,12 +18,11 @@
 #ifndef RAJA_VIEW_HPP
 #define RAJA_VIEW_HPP
 
+#include <array>
 #include <type_traits>
 
 #include "RAJA/config.hpp"
-
 #include "RAJA/pattern/atomic.hpp"
-
 #include "RAJA/util/IndexLayout.hpp"
 #include "RAJA/util/Layout.hpp"
 #include "RAJA/util/OffsetLayout.hpp"
@@ -81,14 +80,14 @@ RAJA_INLINE View<ValueType, IndexLayout<n_dims, IndexType, IndexTypes...> > make
 // select certain indices from a tuple, given a curated index sequence
 // returns linear index of layout(ar...)
 template <typename Lay, typename Tup, camp::idx_t... Idxs>
-RAJA_HOST_DEVICE RAJA_INLINE 
+RAJA_HOST_DEVICE RAJA_INLINE
 auto selecttuple( Lay lyout, Tup&& tup, camp::idx_seq<Idxs...> ) ->
   decltype(
             lyout(
               camp::get<Idxs>(std::forward<Tup>(tup))...
             )
           )
-{ 
+{
   return lyout(
                 camp::get<Idxs>(std::forward<Tup>(tup))...
               );
@@ -234,7 +233,7 @@ struct MultiView {
     {
       RAJA_ABORT_OR_THROW( "Negative index while accessing array of pointers.\n" );
     }
-    
+
     auto idx = stripIndexType( removenth<LayoutType, P2Pidx>( layout, camp::forward_as_tuple( ar... ) ) );
     return data[pidx][idx];
   }
@@ -296,6 +295,89 @@ RAJA_INLINE AtomicViewWrapper<ViewType, AtomicPolicy> make_atomic_view(
   return RAJA::AtomicViewWrapper<ViewType, AtomicPolicy>(view);
 }
 
+struct layout_left {
+};
+struct layout_right {
+};
+
+template <typename LAYOUT>
+struct Reshape;
+
+namespace detail
+{
+template <typename T>
+constexpr auto get_last_index(T last)
+{
+  return last;
+}
+
+template <typename T, typename... Args>
+constexpr auto get_last_index(T, Args... args)
+{
+  return get_last_index(args...);
+}
+}  // namespace detail
+
+template <std::size_t... Is>
+struct Reshape<std::index_sequence<Is...>> {
+  template <typename T, typename... Ts>
+  static auto get(T *ptr, Ts... s)
+  {
+    constexpr int N = sizeof...(Ts);
+    std::array<RAJA::idx_t, N> extent{s...};
+
+    auto custom_layout =
+        RAJA::make_permuted_layout(extent, std::array<RAJA::idx_t, N>{Is...});
+
+    constexpr auto unit_stride = detail::get_last_index(Is...);
+    using view_t = RAJA::View<T, RAJA::Layout<N, RAJA::Index_type, unit_stride>>;
+
+    return view_t(ptr, custom_layout);
+  }
+};
+
+template <>
+struct Reshape<layout_right> {
+  template <typename T, typename... Ts>
+  static auto get(T *ptr, Ts... s)
+  {
+    constexpr int N = sizeof...(Ts);
+    using view_t = RAJA::View<T, RAJA::Layout<N, RAJA::Index_type, N - 1>>;
+
+    return view_t(ptr, s...);
+  }
+};
+
+namespace detail
+{
+
+template <std::size_t... Is>
+constexpr std::array<RAJA::idx_t, sizeof...(Is)> make_reverse_array(
+    std::index_sequence<Is...>)
+{
+  return std::array<RAJA::idx_t, sizeof...(Is)>{sizeof...(Is) - 1U - Is...};
+}
+
+}  // namespace detail
+
+template <>
+struct Reshape<layout_left> {
+  template <typename T, typename... Ts>
+  static auto get(T *ptr, Ts... s)
+  {
+    constexpr int N = sizeof...(Ts);
+
+    std::array<RAJA::idx_t, N> extent{s...};
+
+    constexpr auto reverse_array =
+        detail::make_reverse_array(std::make_index_sequence<N>{});
+
+    auto reverse_layout = RAJA::make_permuted_layout(extent, reverse_array);
+    using view_t = RAJA::View<T, RAJA::Layout<N, RAJA::Index_type, 0U>>;
+
+    return view_t(ptr, reverse_layout);
+  }
+};
 
 }  // namespace RAJA