[QST] how to fix the compiling error: static assertion failed with "Vectors implied by the thread map must be divisible by the access type."

What is your question?
I am trying to change the type in example '24_gemm_grouped' from cutlass::half_t to double. I have change ThreadblockShape/WarpShape/InstructionShape. it works fine for class GemmBatched

  // Gemm operator cutlass_tensorop_f16_s16816gemm_f16_128x128_32x4_nt_align8
  using GemmBatched = cutlass::gemm::device::GemmUniversal<
    ElementA, LayoutA,
    ElementB, LayoutB,
    ElementOutput,   LayoutC,
    ElementAccumulator,
    cutlass::arch::OpClassTensorOp,
    cutlass::arch::Sm80,
    cutlass::gemm::GemmShape<128, 128, 16>,
    cutlass::gemm::GemmShape<32, 64, 16>,
    cutlass::gemm::GemmShape<8, 8, 4>,
    cutlass::epilogue::thread::LinearCombination<
      ElementOutput,
      128 / cutlass::sizeof_bits<ElementOutput>::value,
      ElementAccumulator,
      ElementAccumulator
    >,
    cutlass::gemm::threadblock::GemmIdentityThreadblockSwizzle<8>,
    4
  >;

I also do the similar change in class GemmKernel, but compiler reports "cutlass-main/include/cutlass/transform/threadblock/predicated_tile_access_iterator.h(360): error: static assertion failed with "Vectors implied by the thread map must be divisible by the access type."" How can I fix it?

  using GemmKernel = typename cutlass::gemm::kernel::DefaultGemmGrouped<
    ElementA,
    LayoutA,
    cutlass::ComplexTransform::kNone,
    8,
    ElementB,
    LayoutB,
    cutlass::ComplexTransform::kNone,
    8,
    ElementOutput, LayoutC,
    ElementAccumulator,
    cutlass::arch::OpClassTensorOp,
    cutlass::arch::Sm80,
    cutlass::gemm::GemmShape<128, 128, 16>,
    cutlass::gemm::GemmShape<32, 64, 16>,
    cutlass::gemm::GemmShape<8, 8, 4>,
    cutlass::epilogue::thread::LinearCombination<
        ElementOutput, 128 / cutlass::sizeof_bits<ElementOutput>::value,
        ElementAccumulator, ElementAccumulator>,
    // NOTE: Threadblock swizzling is currently not supported by CUTLASS's grouped kernels.
    // This parameter is passed in at present to match the APIs of other kernels. The parameter
    // is unused within the kernel.
    cutlass::gemm::threadblock::GemmBatchedIdentityThreadblockSwizzle,
    4>::GemmKernel;

  using GemmGrouped = cutlass::gemm::device::GemmGrouped<GemmKernel>;

Thanks

Start with cutlass-main/include/cutlass/transform/threadblock/predicated_tile_access_iterator.h at the reported assertion, then compare the GemmBatched and GemmKernel definitions in example 24_gemm_grouped. Check how changing ElementA and ElementB to double affects the thread map and access type. Done means the grouped example compiles without the divisibility assertion.