Use `static constexpr` for VS compilation (#342)

* static constexpr should be used in cuda/reducer.cuh, otherwise compilation fails in VS

* modify torch/include/ATen/Parallel.h in testing.yml

* update

* update

* update

* typo

* typo

* typo

* remove prints
Co-authored-by: zenghongtai <1518445275@qq.com>
Co-authored-by: rusty1s <matthias.fey@tu-dortmund.de>

.github/workflows/building.yml

@@ -59,6 +59,14 @@ jobs:
           python -c "import torch; print('PyTorch:', torch.__version__)"
           python -c "import torch; print('CUDA:', torch.version.cuda)"
 
+      - name: Patch PyTorch static constexpr on Windows
+        if: ${{ runner.os == 'Windows' }}
+        run: |
+          Torch_DIR=`python -c 'import os; import torch; print(os.path.dirname(torch.__file__))'`
+          sed -i '31,38c\
+          TORCH_API void lazy_init_num_threads();' ${Torch_DIR}/include/ATen/Parallel.h
+        shell: bash
+
       - name: Set version
         if: ${{ runner.os != 'macOS' }}
         run: |

.github/workflows/testing.yml

@@ -29,6 +29,14 @@ jobs:
         run: |
           pip install torch==${{ matrix.torch-version }} --extra-index-url https://download.pytorch.org/whl/cpu
 
+      - name: Patch PyTorch static constexpr on Windows
+        if: ${{ runner.os == 'Windows' }}
+        run: |
+          Torch_DIR=`python -c 'import os; import torch; print(os.path.dirname(torch.__file__))'`
+          sed -i '31,38c\
+          TORCH_API void lazy_init_num_threads();' ${Torch_DIR}/include/ATen/Parallel.h
+        shell: bash
+
       - name: Install main package
         run: |
           pip install -e .[test]

csrc/cuda/reducer.cuh

@@ -16,27 +16,27 @@ const std::map<std::string, ReductionType> reduce2REDUCE = {
   [&] {                                                                        \
     switch (reduce2REDUCE.at(reduce)) {                                        \
     case SUM: {                                                                \
-      const ReductionType REDUCE = SUM;                                        \
+      static constexpr ReductionType REDUCE = SUM;                                        \
       return __VA_ARGS__();                                                    \
     }                                                                          \
     case MEAN: {                                                               \
-      const ReductionType REDUCE = MEAN;                                       \
+      static constexpr ReductionType REDUCE = MEAN;                                       \
       return __VA_ARGS__();                                                    \
     }                                                                          \
     case MUL: {                                                                \
-      const ReductionType REDUCE = MUL;                                        \
+      static constexpr ReductionType REDUCE = MUL;                                        \
       return __VA_ARGS__();                                                    \
     }                                                                          \
     case DIV: {                                                                \
-      const ReductionType REDUCE = DIV;                                        \
+      static constexpr ReductionType REDUCE = DIV;                                        \
       return __VA_ARGS__();                                                    \
     }                                                                          \
     case MIN: {                                                                \
-      const ReductionType REDUCE = MIN;                                        \
+      static constexpr ReductionType REDUCE = MIN;                                        \
       return __VA_ARGS__();                                                    \
     }                                                                          \
     case MAX: {                                                                \
-      const ReductionType REDUCE = MAX;                                        \
+      static constexpr ReductionType REDUCE = MAX;                                        \
       return __VA_ARGS__();                                                    \
     }                                                                          \
     }                                                                          \