refactor

src/include/gridwise_convolution_implicit_gemm_v3_lds_double_buffer_nchw_cyxk_nkhw.hip.hpp

@@ -5,9 +5,8 @@
 #include "ConstantMatrixDescriptor.hip.hpp"
 #include "blockwise_generic_tensor_slice_op.hip.hpp"
 #include "blockwise_gemm.hip.hpp"
-#include "threadwise_tensor_slice_op.hip.hpp"
 
-// define B = merge(N, Ho, Wo)
+// define B = merge(N0, Ho, Wo)
 template <index_t GridSize,
           index_t BlockSize,
           class Float,
@@ -42,7 +41,7 @@ struct GridwiseConvolutionImplicitGemm_v3_lds_double_buffer_nchw_cyxk_nkhw
                         Float* const __restrict__ p_out_global) const
     {
         // this is a mess
-        // TODO: fidn more elegent way of specifying (or calculating) performance parameters
+        // TODO: find more elegent way of specifying (or calculating) performance parameters
         static_assert(N2 == GemmNPerThreadSubC, "wrong!");
         static_assert((N1 * N2 * BPerBlock) %
                               (GemmNPerThreadSubC * GemmNLevel0Cluster * GemmNLevel1Cluster) ==
@@ -144,46 +143,34 @@ struct GridwiseConvolutionImplicitGemm_v3_lds_double_buffer_nchw_cyxk_nkhw
         //     be careful of LDS alignment
         constexpr auto wei_c_k_block_desc = make_ConstantTensorDescriptor_aligned(
             Sequence<CPerBlock, KPerBlock>{},
-            Number<mod_conv::max(WeiBlockCopyDataPerAccess_K, GemmDataPerReadA)>{});
+            Number<mod_conv::lcm(WeiBlockCopyDataPerAccess_K, GemmDataPerReadA)>{});
 
         // operator for blockwise copy of weight into LDS
         //     slice a tensor, and copy it into another tensor
         //     this copy operator already have blockwise offset built-in
         const auto blockwise_wei_copy =
-#if 0
             BlockwiseGenericTensorSliceCopy_v1<BlockSize,
-                                                Float,
-                                                decltype(wei_c_k_global_desc),
-                                                decltype(wei_c_k_block_desc),
-                                                decltype(wei_c_k_block_desc.GetLengths()),
-                                                WeiBlockCopySubLengths_C_K,
-                                                WeiBlockCopyClusterLengths_C_K,
-                                                Sequence<0, 1>, // thread_arrange_order [C, K]
-                                                Sequence<0, 1>, // src_access_order [C, K]
-                                                Sequence<0, 1>, // dst_access_order [C, K]
-                                                WeiBlockCopyDataPerAccess_K,
-                                                WeiBlockCopyDataPerAccess_K>(
+                                               Float,
+                                               decltype(wei_c_k_global_desc),
+                                               decltype(wei_c_k_block_desc),
+                                               decltype(wei_c_k_block_desc.GetLengths()),
+                                               WeiBlockCopySubLengths_C_K,
+                                               WeiBlockCopyClusterLengths_C_K,
+                                               Sequence<0, 1>, // thread_arrange_order [C, K]
+                                               Sequence<0, 1>, // src_access_order [C, K]
+                                               Sequence<0, 1>, // dst_access_order [C, K]
+                                               WeiBlockCopyDataPerAccess_K,
+                                               WeiBlockCopyDataPerAccess_K>(
                 {0, k_block_data_on_global}, {0, 0});
-#else
-            Blockwise2dTensorCopy3<BlockSize,
-                                   Float,
-                                   decltype(wei_c_k_global_desc),
-                                   decltype(wei_c_k_block_desc),
-                                   decltype(wei_c_k_block_desc.GetLengths()),
-                                   WeiBlockCopyDataPerAccess_K>({0, k_block_data_on_global},
-                                                                {0, 0});
-#endif
 
-            // GEMM definition
-            // c_mtx += transpose(a_mtx) * b_mtx
-            //     a_mtx[CPerBlock, KPerBlock] is in LDS
-            //     b_mtx[CPerBlocl, N1 * BPerBlock * N2] is in LDS
-            //     c_mtx[KPerBlock, N1 * BPerBlock * N2] is distributed among threads, and saved in
-            //     register
-            constexpr auto a_c_k_block_mtx_desc =
-                make_ConstantMatrixDescriptor(Number<CPerBlock>{},
-                                              Number<KPerBlock>{},
-                                              Number<wei_c_k_block_desc.GetStride(I0)>{});
+        // GEMM definition
+        // c_mtx += transpose(a_mtx) * b_mtx
+        //     a_mtx[CPerBlock, KPerBlock] is in LDS
+        //     b_mtx[CPerBlocl, N1 * BPerBlock * N2] is in LDS
+        //     c_mtx[KPerBlock, N1 * BPerBlock * N2] is distributed among threads, and saved in
+        //     register
+        constexpr auto a_c_k_block_mtx_desc = make_ConstantMatrixDescriptor(
+            Number<CPerBlock>{}, Number<KPerBlock>{}, Number<wei_c_k_block_desc.GetStride(I0)>{});
 
         constexpr auto b_c_n1bn2_block_mtx_desc =
             make_ConstantMatrixDescriptor(Number<CPerBlock>{},
@@ -228,7 +215,7 @@ struct GridwiseConvolutionImplicitGemm_v3_lds_double_buffer_nchw_cyxk_nkhw
         };
 
         // LDS allocation for input and weight: be careful of alignment
-        constexpr index_t max_align = mod_conv::max(InBlockCopyDstDataPerWrite_N2,
+        constexpr index_t max_align = mod_conv::lcm(InBlockCopyDstDataPerWrite_N2,
                                                     WeiBlockCopyDataPerAccess_K,
                                                     GemmDataPerReadA,
                                                     GemmDataPerReadB);
@@ -261,18 +248,8 @@ struct GridwiseConvolutionImplicitGemm_v3_lds_double_buffer_nchw_cyxk_nkhw
 
                 // LDS double buffer: preload data into LDS
                 {
-                    Float p_in_register_clipboard[blockwise_in_copy.GetRegisterClipboardSize()];
-                    Float p_wei_register_clipboard[blockwise_wei_copy.GetRegisterClipboardSize()];
-
-                    blockwise_in_copy.RunLoadRegisterClipboard(p_in_block_on_global,
-                                                               p_in_register_clipboard);
-                    blockwise_wei_copy.RunLoadRegisterClipboard(p_wei_block_on_global,
-                                                                p_wei_register_clipboard);
-
-                    blockwise_in_copy.RunStoreRegisterClipboard(p_in_register_clipboard,
-                                                                p_in_block_double);
-                    blockwise_wei_copy.RunStoreRegisterClipboard(p_wei_register_clipboard,
-                                                                 p_wei_block_double);
+                    blockwise_in_copy.Run(p_in_block_on_global, p_in_block_double);
+                    blockwise_wei_copy.Run(p_wei_block_on_global, p_wei_block_double);
                 }
 
                 // LDS double buffer: main body
@@ -413,7 +390,8 @@ struct GridwiseConvolutionImplicitGemm_v3_lds_double_buffer_nchw_cyxk_nkhw
                 p_out_thread_on_global,
                 {0, 0, 0, 0, 0, 0, 0, 0},
                 out_n0_n1_n2_k0_k1_k2_h_w_thread_desc.GetLengths(),
-                arithmetic_sequence_gen<0, 8, 1>::SeqType{});
+                arithmetic_sequence_gen<0, 8, 1>::SeqType{},
+                Number<1>{});
         }
     }
 };

src/include/gridwise_convolution_implicit_gemm_v3_nchw_cyxk_nkhw.hip.hpp

@@ -5,9 +5,8 @@
 #include "ConstantMatrixDescriptor.hip.hpp"
 #include "blockwise_generic_tensor_slice_op.hip.hpp"
 #include "blockwise_gemm.hip.hpp"
-#include "threadwise_tensor_slice_op.hip.hpp"
 
-// define B = merge(N, Ho, Wo)
+// define B = merge(N0, Ho, Wo)
 template <index_t GridSize,
           index_t BlockSize,
           class Float,
@@ -42,7 +41,7 @@ struct GridwiseConvolutionImplicitGemm_v3_nchw_cyxk_nkhw
                         Float* const __restrict__ p_out_global) const
     {
         // this is a mess
-        // TODO: fidn more elegent way of specifying (or calculating) performance parameters
+        // TODO: find more elegent way of specifying (or calculating) performance parameters
         static_assert(N2 == GemmNPerThreadSubC, "wrong!");
         static_assert((N1 * N2 * BPerBlock) %
                               (GemmNPerThreadSubC * GemmNLevel0Cluster * GemmNLevel1Cluster) ==
@@ -147,13 +146,12 @@ struct GridwiseConvolutionImplicitGemm_v3_nchw_cyxk_nkhw
         //     be careful of LDS alignment
         constexpr auto wei_c_k_block_desc = make_ConstantTensorDescriptor_aligned(
             Sequence<CPerBlock, KPerBlock>{},
-            Number<mod_conv::max(WeiBlockCopyDataPerAccess_K, GemmDataPerReadA)>{});
+            Number<mod_conv::lcm(WeiBlockCopyDataPerAccess_K, GemmDataPerReadA)>{});
 
         // operator for blockwise copy of weight into LDS
         //     slice a tensor, and copy it into another tensor
         //     this copy operator already have blockwise offset built-in
         auto blockwise_wei_copy =
-#if 1
             BlockwiseGenericTensorSliceCopy_v1<BlockSize,
                                                Float,
                                                decltype(wei_c_k_global_desc),
@@ -167,15 +165,6 @@ struct GridwiseConvolutionImplicitGemm_v3_nchw_cyxk_nkhw
                                                WeiBlockCopyDataPerAccess_K,
                                                WeiBlockCopyDataPerAccess_K>(
                 {0, k_block_data_on_global}, {0, 0});
-#else
-            Blockwise2dTensorCopy3<BlockSize,
-                                   Float,
-                                   decltype(wei_c_k_global_desc),
-                                   decltype(wei_c_k_block_desc),
-                                   decltype(wei_c_k_block_desc.GetLengths()),
-                                   WeiBlockCopyDataPerAccess_K>({0, k_block_data_on_global},
-                                                                {0, 0});
-#endif
 
         // GEMM definition
         // c_mtx += transpose(a_mtx) * b_mtx
@@ -219,8 +208,17 @@ struct GridwiseConvolutionImplicitGemm_v3_nchw_cyxk_nkhw
             GemmDataPerReadA,
             GemmDataPerReadB>{};
 
+        // choose GEMM implementation here
+        const auto run_blockwise_gemm = [&](auto... Xs) {
+#if 1
+            return blockwise_gemm.Run(Xs...);
+#else
+            return blockwise_gemm.Run_asm(Xs...);
+#endif
+        };
+
         // LDS allocation for input and weight: be careful of alignment
-        constexpr index_t max_align = mod_conv::max(InBlockCopyDstDataPerWrite_N2,
+        constexpr index_t max_align = mod_conv::lcm(InBlockCopyDstDataPerWrite_N2,
                                                     WeiBlockCopyDataPerAccess_K,
                                                     GemmDataPerReadA,
                                                     GemmDataPerReadB);
@@ -264,7 +262,7 @@ struct GridwiseConvolutionImplicitGemm_v3_nchw_cyxk_nkhw
 
                     __syncthreads();
 
-                    blockwise_gemm.Run(p_wei_block, p_in_block, p_out_thread);
+                    run_blockwise_gemm(p_wei_block, p_in_block, p_out_thread);
 
                     __syncthreads();
                 }
@@ -294,7 +292,6 @@ struct GridwiseConvolutionImplicitGemm_v3_nchw_cyxk_nkhw
 
                     __syncthreads();
 
-                    // move on C: C_N1_B_N2, C_K
                     blockwise_in_copy.MoveSlicingWindowOnSourceTensor(
                         I0, Number<CPerBlock>{}, True);
 
@@ -366,7 +363,8 @@ struct GridwiseConvolutionImplicitGemm_v3_nchw_cyxk_nkhw
                 p_out_thread_on_global,
                 {0, 0, 0, 0, 0, 0, 0, 0},
                 out_n0_n1_n2_k0_k1_k2_h_w_thread_desc.GetLengths(),
-                arithmetic_sequence_gen<0, 8, 1>::SeqType{});
+                arithmetic_sequence_gen<0, 8, 1>::SeqType{},
+                Number<1>{});
         }
     }
 };

src/include/gridwise_convolution_implicit_gemm_v4_lds_double_buffer_nchw_kcyx_nkhw.hip.hpp

@@ -7,7 +7,7 @@
 #include "blockwise_gemm.hip.hpp"
 #include "threadwise_generic_tensor_slice_op.hip.hpp"
 
-// define B = merge(N, Ho, Wo)
+// define B = merge(N0, Ho, Wo)
 template <index_t GridSize,
           index_t BlockSize,
           class Float,
@@ -165,12 +165,11 @@ struct GridwiseConvolutionImplicitGemm_v4_lds_double_buffer_nchw_kcyx_nkhw
         //     be careful of LDS alignment
         constexpr auto wei_e_k_block_desc = make_ConstantTensorDescriptor_aligned(
             Sequence<EPerBlock, KPerBlock>{},
-            Number<mod_conv::max(WeiBlockCopyDstDataPerWrite_K, GemmDataPerReadA)>{});
+            Number<mod_conv::lcm(WeiBlockCopyDstDataPerWrite_K, GemmDataPerReadA)>{});
 
-// operator for blockwise copy of weight into LDS
-//     slice a tensor, and copy it into another tensor
-//     this copy operator already have blockwise offset built-in
-#if 1
+        // operator for blockwise copy of weight into LDS
+        //     slice a tensor, and copy it into another tensor
+        //     this copy operator already have blockwise offset built-in
         auto blockwise_wei_copy =
             BlockwiseGenericTensorSliceCopy_v1<BlockSize,
                                                Float,
@@ -185,22 +184,6 @@ struct GridwiseConvolutionImplicitGemm_v4_lds_double_buffer_nchw_kcyx_nkhw
                                                WeiBlockCopySrcDataPerRead_E,
                                                WeiBlockCopyDstDataPerWrite_K>(
                 {0, k_block_data_on_global}, {0, 0});
-#else
-        constexpr auto map_k_e_2_e_k = Sequence<1, 0>{};
-
-        auto blockwise_wei_copy = BlockwiseTensorSliceReorderCopy_v3<
-            BlockSize,
-            Float,
-            decltype(wei_e_k_global_desc.ReorderGivenNew2Old(map_k_e_2_e_k)),
-            decltype(wei_e_k_block_desc),
-            decltype(wei_e_k_block_desc.GetLengths().ReorderGivenNew2Old(map_k_e_2_e_k)),
-            decltype(WeiBlockCopySubLengths_E_K::ReorderGivenNew2Old(map_k_e_2_e_k)),
-            decltype(WeiBlockCopyClusterLengths_E_K::ReorderGivenNew2Old(map_k_e_2_e_k)),
-            Sequence<1, 0>, // MapDst2Src
-            WeiBlockCopyThreadClusterArrangeOrder,
-            WeiBlockCopySrcDataPerRead_E,
-            WeiBlockCopyDstDataPerWrite_K>({k_block_data_on_global, 0}, {0, 0});
-#endif
 
         // GEMM definition
         // c_mtx += transpose(a_mtx) * b_mtx
@@ -254,7 +237,7 @@ struct GridwiseConvolutionImplicitGemm_v4_lds_double_buffer_nchw_kcyx_nkhw
         };
 
         // LDS allocation for input and weight: be careful of alignment
-        constexpr index_t max_align = mod_conv::max(InBlockCopyDstDataPerWrite_N2,
+        constexpr index_t max_align = mod_conv::lcm(InBlockCopyDstDataPerWrite_N2,
                                                     WeiBlockCopyDstDataPerWrite_K,
                                                     GemmDataPerReadA,
                                                     GemmDataPerReadB);
@@ -273,18 +256,6 @@ struct GridwiseConvolutionImplicitGemm_v4_lds_double_buffer_nchw_kcyx_nkhw
         // zero out threadwise output
         threadwise_matrix_set_zero(c_k0k2_n1n2_thread_mtx_desc, p_out_thread);
 
-#if 0
-        if(get_block_1d_id() == 0)
-        {
-            printf("id %5u %5u: "
-                   "mThreadSrcOffset %u, mThreadDstOffset %u \n",
-                   get_block_1d_id(),
-                   get_thread_local_1d_id(),
-                   blockwise_wei_copy.mThreadSrcOffset,
-                   blockwise_wei_copy.mThreadDstOffset);
-        }
-#endif
-
         const Float* p_wei_block_on_global = p_wei_global;
 
         // LDS double buffer: preload data into LDS

src/include/gridwise_convolution_implicit_gemm_v4_nchw_kcyx_nkhw.hip.hpp

@@ -7,7 +7,7 @@
 #include "blockwise_gemm.hip.hpp"
 #include "threadwise_generic_tensor_slice_op.hip.hpp"
 
-// define B = merge(N, Ho, Wo)
+// define B = merge(N0, Ho, Wo)
 template <index_t GridSize,
           index_t BlockSize,
           class Float,
@@ -30,10 +30,16 @@ template <index_t GridSize,
           index_t GemmDataPerReadB,
           class InBlockCopySubLengths_E_N1_B_N2,
           class InBlockCopyClusterLengths_E_N1_B_N2,
+          class InBlockCopyThreadClusterArrangeOrder,
+          class InBlockCopySrcAccessOrder,
+          class InBlockCopyDstAccessOrder,
           index_t InBlockCopySrcDataPerRead_B,
           index_t InBlockCopyDstDataPerWrite_N2,
           class WeiBlockCopySubLengths_E_K,
           class WeiBlockCopyClusterLengths_E_K,
+          class WeiBlockCopyThreadClusterArrangeOrder,
+          class WeiBlockCopySrcAccessOrder,
+          class WeiBlockCopyDstAccessOrder,
           index_t WeiBlockCopySrcDataPerRead_E,
           index_t WeiBlockCopyDstDataPerWrite_K>
 struct GridwiseConvolutionImplicitGemm_v4_nchw_kcyx_nkhw
@@ -146,19 +152,20 @@ struct GridwiseConvolutionImplicitGemm_v4_nchw_kcyx_nkhw
         // input blockwise copy
         //     slice a merged tensor, reorder and copy to a normal tensor
         //     this copy operator already has blockwise offset built-in
-        auto blockwise_in_copy = BlockwiseGenericTensorSliceCopy_v1<
-            BlockSize,
-            Float,
-            decltype(in_e_n1_b_n2_global_merged_desc),
-            decltype(in_e_n1_b_n2_block_desc),
-            decltype(in_e_n1_b_n2_block_desc.GetLengths()),
-            InBlockCopySubLengths_E_N1_B_N2,
-            InBlockCopyClusterLengths_E_N1_B_N2,
-            Sequence<0, 1, 3, 2>, // thread_arrange_order [E, N1, N2, B]
-            Sequence<0, 1, 3, 2>, // src_access_order [E, N1, N2, B]
-            Sequence<0, 1, 2, 3>, // dst_access_order [E, N1, B, N2]
-            InBlockCopySrcDataPerRead_B,
-            InBlockCopyDstDataPerWrite_N2>({0, 0, b_block_data_on_global, 0}, {0, 0, 0, 0});
+        auto blockwise_in_copy =
+            BlockwiseGenericTensorSliceCopy_v1<BlockSize,
+                                               Float,
+                                               decltype(in_e_n1_b_n2_global_merged_desc),
+                                               decltype(in_e_n1_b_n2_block_desc),
+                                               decltype(in_e_n1_b_n2_block_desc.GetLengths()),
+                                               InBlockCopySubLengths_E_N1_B_N2,
+                                               InBlockCopyClusterLengths_E_N1_B_N2,
+                                               InBlockCopyThreadClusterArrangeOrder,
+                                               InBlockCopySrcAccessOrder,
+                                               InBlockCopyDstAccessOrder,
+                                               InBlockCopySrcDataPerRead_B,
+                                               InBlockCopyDstDataPerWrite_N2>(
+                {0, 0, b_block_data_on_global, 0}, {0, 0, 0, 0});
 
         // weight tensor
         //     tensor descriptor in device memory, src of blockwise copy
@@ -169,7 +176,7 @@ struct GridwiseConvolutionImplicitGemm_v4_nchw_kcyx_nkhw
         //     be careful of LDS alignment
         constexpr auto wei_e_k_block_desc = make_ConstantTensorDescriptor_aligned(
             Sequence<EPerBlock, KPerBlock>{},
-            Number<mod_conv::max(WeiBlockCopyDstDataPerWrite_K, GemmDataPerReadA)>{});
+            Number<mod_conv::lcm(WeiBlockCopyDstDataPerWrite_K, GemmDataPerReadA)>{});
 
         // operator for blockwise copy of weight into LDS
         //     slice a tensor, and copy it into another tensor
@@ -182,9 +189,9 @@ struct GridwiseConvolutionImplicitGemm_v4_nchw_kcyx_nkhw
                                                decltype(wei_e_k_block_desc.GetLengths()),
                                                WeiBlockCopySubLengths_E_K,
                                                WeiBlockCopyClusterLengths_E_K,
-                                               Sequence<1, 0>, // thread_arrange_order [K, E]
-                                               Sequence<1, 0>, // src_access_order [K, E]
-                                               Sequence<0, 1>, // dst_access_order [E, K]
+                                               WeiBlockCopyThreadClusterArrangeOrder,
+                                               WeiBlockCopySrcAccessOrder,
+                                               WeiBlockCopyDstAccessOrder,
                                                WeiBlockCopySrcDataPerRead_E,
                                                WeiBlockCopyDstDataPerWrite_K>(
                 {0, k_block_data_on_global}, {0, 0});
@@ -231,8 +238,17 @@ struct GridwiseConvolutionImplicitGemm_v4_nchw_kcyx_nkhw
             GemmDataPerReadA,
             GemmDataPerReadB>{};
 
+        // choose GEMM implementation here
+        const auto run_blockwise_gemm = [&](auto... Xs) {
+#if 1
+            return blockwise_gemm.Run(Xs...);
+#else
+            return blockwise_gemm.Run_asm(Xs...);
+#endif
+        };
+
         // LDS allocation for input and weight: be careful of alignment
-        constexpr index_t max_align = mod_conv::max(InBlockCopyDstDataPerWrite_N2,
+        constexpr index_t max_align = mod_conv::lcm(InBlockCopyDstDataPerWrite_N2,
                                                     WeiBlockCopyDstDataPerWrite_K,
                                                     GemmDataPerReadA,
                                                     GemmDataPerReadB);
@@ -254,24 +270,13 @@ struct GridwiseConvolutionImplicitGemm_v4_nchw_kcyx_nkhw
         // do work
         for(index_t e = 0; e < E; e += EPerBlock)
         {
-#if 0
-            if(e == 0 * EPerBlock && get_block_1d_id() == 0)
-            {
-                printf("id %5u %5u: "
-                       "mThreadSrcOffset %u, mThreadDstOffset %u \n",
-                       get_block_1d_id(),
-                       get_thread_local_1d_id(),
-                       blockwise_wei_copy.mThreadSrcOffset,
-                       blockwise_wei_copy.mThreadDstOffset);
-            }
-#endif
             // marching slicing window
             blockwise_in_copy.Run(p_in_global, p_in_block);
             blockwise_wei_copy.Run(p_wei_global, p_wei_block);
 
             __syncthreads();
 
-            blockwise_gemm.Run(p_wei_block, p_in_block, p_out_thread);
+            run_blockwise_gemm(p_wei_block, p_in_block, p_out_thread);
 
             __syncthreads();
 
@@ -335,7 +340,8 @@ struct GridwiseConvolutionImplicitGemm_v4_nchw_kcyx_nkhw
                 p_out_thread_on_global,
                 {0, 0, 0, 0, 0, 0, 0, 0},
                 out_n0_n1_n2_k0_k1_k2_h_w_thread_desc.GetLengths(),
-                arithmetic_sequence_gen<0, 8, 1>::SeqType{});
+                arithmetic_sequence_gen<0, 8, 1>::SeqType{},
+                Number<1>{});
         }
     }
 };

src/include/integral_constant.hip.hpp

@@ -8,7 +8,7 @@ struct integral_constant
     __host__ __device__ constexpr T Get() const { return value; }
 };
 
-template <class T, index_t X, index_t Y>
+template <class T, T X, T Y>
 __host__ __device__ constexpr auto operator+(integral_constant<T, X>, integral_constant<T, Y>)
 {
     return integral_constant<T, X + Y>{};

src/include/threadwise_generic_tensor_slice_op.hip.hpp

@@ -62,7 +62,7 @@ __device__ void threadwise_generic_tensor_slice_copy_v1(
 #if 1
     ford<decltype(access_lengths)>{}([&](auto access_multi_id) {
         auto data_multi_id_in_access_order      = access_multi_id;
-        data_multi_id_in_access_order[nDim - 1] = access_multi_id[nDim - 1] * DataPerAccess;
+        data_multi_id_in_access_order(nDim - 1) = access_multi_id[nDim - 1] * DataPerAccess;
 
         const auto data_multi_id =
             reorder_array_given_old2new(data_multi_id_in_access_order, DimAccessOrder{});