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/*! \file
    \brief Template for a Block-Ell sparse gemm kernel.
*/

#pragma once

#include "cutlass/cutlass.h"
#include "cutlass/numeric_types.h"
#include "cutlass/arch/arch.h"
#include "cutlass/device_kernel.h"

#include "cutlass/gemm/threadblock/threadblock_swizzle.h"
#include "cutlass/gemm/kernel/ell_gemm.h"

#include "cutlass/gemm/kernel/default_ell_gemm.h"
#include "cutlass/gemm/device/default_gemm_configuration.h"

////////////////////////////////////////////////////////////////////////////////

namespace cutlass {
namespace gemm {
namespace device {

/////////////////////////////////////////////////////////////////////////////////////////////////

/*! Blocked-Ell sparse gemm device-level operator. This is an interface to efficient CUTLASS
  Blocked-Ell kernels that may be invoked from host code.

  The contributions of this class are:
    
    1. At compile time, it maps data types and high-level structural parameters onto 
       specific CUTLASS components.

    2. At runtime, it maps logical arguments to Blocked-Ell problems to kernel parameters.

    3. At runtime, it launches kernels on the device.

  Example of a CUTLASS EllGemm operator is as follows:

    //
    // Instantiate the CUTLASS EllGemm operator.
    //

    cutlass::gemm::device::EllGemm<
      cutlass::half_t,
      cutlass::layout::RowMajor,
      cutlass::half_t,
      cutlass::layout::ColumnMajor,
      cutlass::half_t,
      cutlass::layout::ColumnMajor,
      float, 
      cutlass::arch::OpClassTensorOp, 
      cutlass::arch::Sm80,
      cutlass::gemm::GemmShape<128, 128, 32>,
      cutlass::gemm::GemmShape<64, 64, 32>, 
      cutlass::gemm::GemmShape<16, 8, 16>,
      cutlass::epilogue::thread::LinearCombination<
          cutlass::half_t, 128 / cutlass::sizeof_bits<cutlass::half_t>::value,
          float, float>,
      cutlass::gemm::threadblock::GemmIdentityThreadblockSwizzle<8>, 
      4, // Stages
      128 / cutlass::sizeof_bits<cutlass::half_t>::value, // Alignment A
      128 / cutlass::sizeof_bits<cutlass::half_t>::value  // Alignment B
    > ellgemm_op;

    //
    // Launch the EllGemm operation on the device
    //

    Description of parameters and tensors used to represent the Blocked-Ellpack (ELL) format:
      a_rows              - Rows in the sparse matrix.
      a_cols              - Colums in the sparse matrix.
      BlockedEllA         - Packed matrix (ellValue matrix) that stores non-zero values in 
                            consecutive blocks, whose size is (a_rows * a_ell_num_columns)
      ell_idx             - Blocked-ELL Column indices (ellColInd) matrix, whose size is
                            (a_rows / a_ell_blocksize) * (a_ell_num_columns / a_ell_blocksize)
      a_ell_blocksize     - Size of the ELL-Blocks.
      a_ell_num_columns   - Number of columns in the Blocked-Ellpack format (ellValue columns)
      B                   - Input dense matrix whose size is (a_cols * n)
      C/D                 - Output dense matrix whose size is (a_rows * n)

    cutlass::Status status = ellgemm_op({
      {a_rows, n, a_cols},  // GemmCoord problem_size
      {BlockedEllA, lda},   // TensorRef<cutlass::half_t, layout::RowMajor> ref_BlockedEllA
      {B, ldb},             // TensorRef<cutlass::half_t, layout::ColumnMajor> ref_B,
      {C, ldc},             // TensorRef<float, layout::ColumnMajor> ref_C,
      {D, ldd},             // TensorRef<float, layout::ColumnMajor> ref_D,
      ell_idx,              // Blocked-ELL Column indices or ellColInd matrix (const int*)
      a_ell_num_columns,    // Columns in the Blocked-Ellpack (ellValue) matrix (int)
      a_ell_blocksize,      // Size of the ELL-Blocks (int)
      a_ell_base,           // Base index of ellColInd (int) - Zero or One
      {alpha, beta}         // EpilogueOutputOp::Params epilogue_op_params
    });

  A simplified view of the template is listed below.

    template <
      /// Element type for A matrix operand
      typename ElementA,
      
      /// Layout type for A matrix operand
      typename LayoutA,
      
      /// Element type for B matrix operand
      typename ElementB,
      
      /// Layout type for B matrix operand
      typename LayoutB,
      
      /// Element type for C and D matrix operands
      typename ElementC,
      
      /// Layout type for C and D matrix operands
      typename LayoutC,
      
      /// Element type for internal accumulation
      typename ElementAccumulator,

      /// Operator class tag
      typename OperatorClass,
      
      /// Tag indicating architecture to tune for.  This is the minimum SM that
      /// supports the intended feature. The device kernel can be built
      /// targeting any SM larger than this number.
      typename ArchTag,
      
      /// Threadblock-level tile size (concept: GemmShape)
      typename ThreadblockShape,
      
      /// Warp-level tile size (concept: GemmShape)
      typename WarpShape,
      
      /// Warp-level tile size (concept: GemmShape)
      typename InstructionShape,
      
      /// Epilogue output operator
      typename EpilogueOutputOp,
      
      /// Threadblock-level swizzling operator
      typename ThreadblockSwizzle,
      
      /// Number of stages used in the pipelined mainloop
      int Stages

      /// Access granularity of A matrix in units of elements
      int AlignmentA,

      /// Access granularity of B matrix in units of elements
      int AlignmentB,

      /// Supports split-K with serial reduction
      bool SplitKSerial,

      /// Operation performed by GEMM
      typename Operator,

      /// Sparse matrix is A or not
      bool IsASparse
    >
    class EllGemm;
*/
template <
    /// Element type for A matrix operand
    typename ElementA_,
    /// Layout type for A matrix operand
    typename LayoutA_,
    /// Element type for B matrix operand
    typename ElementB_,
    /// Layout type for B matrix operand
    typename LayoutB_,
    /// Element type for C and D matrix operands
    typename ElementC_,
    /// Layout type for C and D matrix operands
    typename LayoutC_,
    /// Element type for internal accumulation
    typename ElementAccumulator_ = ElementC_,
    /// Operator class tag
    typename OperatorClass_ = arch::OpClassTensorOp,
    /// Tag indicating architecture to tune for
    typename ArchTag_ = arch::Sm80,
    /// Threadblock-level tile size (concept: GemmShape)
    typename ThreadblockShape_ = typename DefaultGemmConfiguration<
        OperatorClass_, ArchTag_, ElementA_, ElementB_, ElementC_,
        ElementAccumulator_>::ThreadblockShape,
    /// Warp-level tile size (concept: GemmShape)
    typename WarpShape_ = typename DefaultGemmConfiguration<
        OperatorClass_, ArchTag_, ElementA_, ElementB_, ElementC_,
        ElementAccumulator_>::WarpShape,
    /// Instruction-level tile size (concept: GemmShape)
    typename InstructionShape_ = typename DefaultGemmConfiguration<
        OperatorClass_, ArchTag_, ElementA_, ElementB_, ElementC_,
        ElementAccumulator_>::InstructionShape,
    /// Epilogue output operator
    typename EpilogueOutputOp_ = typename DefaultGemmConfiguration<
        OperatorClass_, ArchTag_, ElementA_, ElementB_, ElementC_,
        ElementAccumulator_>::EpilogueOutputOp,
    /// Threadblock-level swizzling operator
    typename ThreadblockSwizzle_ =
        typename threadblock::GemmIdentityThreadblockSwizzle<>,
    /// Number of stages used in the pipelined mainloop
    int Stages =
        DefaultGemmConfiguration<OperatorClass_, ArchTag_, ElementA_, ElementB_,
                                 ElementC_, ElementAccumulator_>::kStages,
    /// Access granularity of A matrix in units of elements
    int AlignmentA =
        DefaultGemmConfiguration<OperatorClass_, ArchTag_, ElementA_, ElementB_,
                                 ElementC_, ElementAccumulator_>::kAlignmentA,
    /// Access granularity of B matrix in units of elements
    int AlignmentB =
        DefaultGemmConfiguration<OperatorClass_, ArchTag_, ElementA_, ElementB_,
                                 ElementC_, ElementAccumulator_>::kAlignmentB,
    /// If true, kernel supports split-K with serial reduction
    bool SplitKSerial = false,
    /// Operation performed by GEMM
    typename Operator_ = typename DefaultGemmConfiguration<
        OperatorClass_, ArchTag_, ElementA_, ElementB_, ElementC_,
        ElementAccumulator_>::Operator,
    /// Sparse matrix is A or not
    bool IsASparse = true
    >
class EllGemm {
 public:

  using ElementA = ElementA_;
  using LayoutA = LayoutA_;
  using TensorRefA = TensorRef<ElementA const, LayoutA>;
  using ElementB = ElementB_;
  using LayoutB = LayoutB_;
  using TensorRefB = TensorRef<ElementB const, LayoutB>;
  using ElementC = ElementC_;
  using LayoutC = LayoutC_;
  using TensorRefC = TensorRef<ElementC const, LayoutC>;
  using TensorRefD = TensorRef<ElementC, LayoutC>;
  using ElementAccumulator = ElementAccumulator_;
  using OperatorClass = OperatorClass_;
  using ArchTag = ArchTag_;
  using ThreadblockShape = ThreadblockShape_;
  using WarpShape = WarpShape_;
  using InstructionShape = InstructionShape_;
  using EpilogueOutputOp = EpilogueOutputOp_;
  using ThreadblockSwizzle = ThreadblockSwizzle_;
  using Operator = Operator_;
  static int const kStages = Stages;
  static int const kAlignmentA = AlignmentA;
  static int const kAlignmentB = AlignmentB;
  static int const kAlignmentC = EpilogueOutputOp::kCount;
  static bool const kSplitKSerial = SplitKSerial;
  static ComplexTransform const kTransformA = ComplexTransform::kNone;
  static ComplexTransform const kTransformB = ComplexTransform::kNone;
  static bool const kIsASparse = IsASparse;

  /// Define the kernel
  using GemmKernel = typename kernel::DefaultEllGemm<
    ElementA,
    LayoutA,
    kAlignmentA,
    ElementB,
    LayoutB,
    kAlignmentB,
    ElementC,
    LayoutC,
    ElementAccumulator,
    OperatorClass,
    ArchTag,
    ThreadblockShape,
    WarpShape,
    InstructionShape,
    EpilogueOutputOp,
    ThreadblockSwizzle,
    kStages,
    kSplitKSerial,
    Operator,
    kIsASparse
  >::GemmKernel;

  /// Argument structure
  struct Arguments {

    //
    // Data members
    //

    GemmCoord problem_size;
    TensorRef<ElementA const, LayoutA> ref_A;
    TensorRef<ElementB const, LayoutB> ref_B;
    TensorRef<ElementC const, LayoutC> ref_C;
    TensorRef<ElementC, LayoutC> ref_D;
    const int* ell_idx;
    int ell_ncol;
    int ell_blocksize;
    int ell_base_idx;
    typename EpilogueOutputOp::Params epilogue;
    int split_k_slices;

    //
    // Methods
    //

    /// Default ctor
    CUTLASS_HOST_DEVICE
    Arguments(): problem_size(0, 0, 0), split_k_slices(1) {

    }

    /// Constructs an Arguments structure 
    CUTLASS_HOST_DEVICE
    Arguments(
      GemmCoord problem_size_,
      TensorRef<ElementA const, LayoutA> ref_A_,
      TensorRef<ElementB const, LayoutB> ref_B_,
      TensorRef<ElementC const, LayoutC> ref_C_,
      TensorRef<ElementC, LayoutC> ref_D_,
      const int* ell_idx_,
      int ell_ncol_,
      int ell_blocksize_,
      int ell_base_idx_,
      typename EpilogueOutputOp::Params epilogue_ = 
        typename EpilogueOutputOp::Params(),
      int split_k_slices = 1
    ):
      problem_size(problem_size_),
      ref_A(ref_A_),
      ref_B(ref_B_),
      ref_C(ref_C_),
      ref_D(ref_D_),
      ell_idx(ell_idx_),
      ell_ncol(ell_ncol_),
      ell_blocksize(ell_blocksize_),
      ell_base_idx(ell_base_idx_),
      epilogue(epilogue_),
      split_k_slices(split_k_slices) {

    }
  };

private:

  /// Kernel parameters object
  typename GemmKernel::Params params_{};

public:

  /// Constructs the GEMM.
  EllGemm() { }

  /// Determines whether the GEMM can execute the given problem.
  static Status can_implement(Arguments const &args) {

    if (!kSplitKSerial && args.split_k_slices > 1) {
      return Status::kErrorInvalidProblem;
    }

    Status status = GemmKernel::can_implement(
      args.problem_size,
      args.ref_A.non_const_ref(),
      args.ref_B.non_const_ref(),
      args.ref_C.non_const_ref(),
      args.ref_D
    );

    if (status != Status::kSuccess) {
      return status;
    }

    return Status::kSuccess;
  }

  /// Gets the workspace size
  static size_t get_workspace_size(Arguments const &args) {
    
    size_t bytes = 0;

    // Determine grid shape
    ThreadblockSwizzle threadblock_swizzle;

    cutlass::gemm::GemmCoord tiled_shape = threadblock_swizzle.get_tiled_shape(
                                              args.problem_size, 
                                              {args.ell_blocksize,
                                              ThreadblockShape::kN, ThreadblockShape::kK},
                                              args.split_k_slices);
      
    tiled_shape.m() *= (args.ell_blocksize + ThreadblockShape::kM - 1 ) / ThreadblockShape::kM;
    
    if (kSplitKSerial && args.split_k_slices > 1) {

      bytes += sizeof(int) * size_t(tiled_shape.m()) * size_t(tiled_shape.n());
    }

    return bytes;
  }

  Status set(Arguments const &args, cutlass::gemm::GemmCoord const &grid_shape, void *workspace){
    // Initialize the Params structure
    params_ = typename GemmKernel::Params{
      args.problem_size,
      grid_shape,
      args.ref_A.non_const_ref(),
      args.ref_B.non_const_ref(),
      args.ref_C.non_const_ref(),
      args.ref_D,
      args.ell_idx,
      args.ell_ncol,
      args.ell_blocksize,
      args.ell_base_idx,
      args.epilogue,
      static_cast<int *>(workspace)
    };
    return Status::kSuccess;
  }

  /// Initializes GEMM state from arguments.
  Status initialize(Arguments const &args, void *workspace = nullptr, cudaStream_t stream = nullptr) {

    // Determine grid shape
    ThreadblockSwizzle threadblock_swizzle;

    cutlass::gemm::GemmCoord grid_shape = threadblock_swizzle.get_tiled_shape(
      args.problem_size, 
      {args.ell_blocksize, ThreadblockShape::kN, ThreadblockShape::kK},
      args.split_k_slices);

    grid_shape.m() *= (args.ell_blocksize + ThreadblockShape::kM - 1 ) / ThreadblockShape::kM;

    if (kSplitKSerial) {
      if (args.split_k_slices > 1) {
        if (!workspace) {
          return Status::kErrorWorkspaceNull;
        }

        size_t bytes = get_workspace_size(args);
      
        cudaError_t result = cudaMemsetAsync(workspace, 0, bytes, stream);

        if (result != cudaSuccess) {
          return Status::kErrorInternal;
        }
      }
    }
    else {

      if (args.split_k_slices > 1) {
        return Status::kErrorInvalidProblem;
      }
    }

    return set(args, grid_shape, workspace);
  }

  /// Lightweight update given a subset of arguments
  Status update(Arguments const &args, void *workspace = nullptr) {
    
    if (kSplitKSerial && args.split_k_slices > 1) {  
      if (!workspace) {
        return Status::kErrorWorkspaceNull;
      }
    }

    params_.ref_A.reset(args.ref_A.non_const_ref().data());
    params_.ref_B.reset(args.ref_B.non_const_ref().data());
    params_.ref_C.reset(args.ref_C.non_const_ref().data());
    params_.ref_D.reset(args.ref_D.data());
    params_.output_op = args.epilogue;
    params_.semaphore = static_cast<int *>(workspace);

    return Status::kSuccess;
  }

  /// Runs the kernel using initialized state.
  Status run(cudaStream_t stream = nullptr) {

    ThreadblockSwizzle threadblock_swizzle;

    dim3 grid = threadblock_swizzle.get_grid_shape(params_.grid_tiled_shape);
    dim3 block(GemmKernel::kThreadCount, 1, 1);

    cudaError_t result;

    int smem_size = int(sizeof(typename GemmKernel::SharedStorage));

    if (smem_size >= (48 << 10)) {
      result = cudaFuncSetAttribute(Kernel<GemmKernel>,
                                    cudaFuncAttributeMaxDynamicSharedMemorySize,
                                    smem_size);

      if (result != cudaSuccess) {
        return Status::kErrorInternal;
      }
    }

    cutlass::Kernel<GemmKernel><<<grid, block, smem_size, stream>>>(params_);

    result = cudaGetLastError();

    return result == cudaSuccess ? Status::kSuccess : Status::kErrorInternal;
  }

  /// Runs the kernel using initialized state.
  Status operator()(cudaStream_t stream = nullptr) {
    return run(stream);
  }

  /// Runs the kernel using initialized state.
  Status operator()(
    Arguments const &args, 
    void *workspace = nullptr, 
    cudaStream_t stream = nullptr) {
    
    Status status = initialize(args, workspace);
    
    if (status == Status::kSuccess) {
      status = run(stream);
    }

    return status;
  }
};

////////////////////////////////////////////////////////////////////////////////

/// Partial specialization for column-major output exchanges problem size and operand.
template <
    /// Element type for A matrix operand
    typename ElementA_,
    /// Layout type for A matrix operand
    typename LayoutA_,
    /// Element type for B matrix operand
    typename ElementB_,
    /// Layout type for B matrix operand
    typename LayoutB_,
    /// Element type for C and D matrix operands
    typename ElementC_,
    /// Element type for internal accumulation
    typename ElementAccumulator_,
    /// Operator class tag
    typename OperatorClass_,
    /// Tag indicating architecture to tune for
    typename ArchTag_,
    /// Threadblock-level tile size (concept: GemmShape)
    typename ThreadblockShape_,
    /// Warp-level tile size (concept: GemmShape)
    typename WarpShape_,
    /// Instruction-level tile size (concept: GemmShape)
    typename InstructionShape_,
    /// Epilogue output operator
    typename EpilogueOutputOp_,
    /// Threadblock-level swizzling operator
    typename ThreadblockSwizzle_,
    /// Number of stages used in the pipelined mainloop
    int Stages,
    /// Access granularity of A matrix in units of elements
    int AlignmentA,
    /// Access granularity of B matrix in units of elements
    int AlignmentB,
    /// If true, kernel supports split-K as a serial reduction
    bool SplitKSerial,
    /// Operation performed by GEMM
    typename Operator_,
    /// Sparse matrix is A or not
    bool IsASparse>
class EllGemm<ElementA_, LayoutA_, ElementB_, LayoutB_, ElementC_,
           layout::ColumnMajor,  // partially specialized on LayoutC
           ElementAccumulator_, OperatorClass_, ArchTag_, ThreadblockShape_,
           WarpShape_, InstructionShape_, EpilogueOutputOp_,
           ThreadblockSwizzle_, Stages, AlignmentA, AlignmentB,
           SplitKSerial, Operator_, IsASparse> {
 public:

  using ElementA = ElementA_;
  using LayoutA = LayoutA_;
  using TensorRefA = TensorRef<ElementA const, LayoutA>;
  using ElementB = ElementB_;
  using LayoutB = LayoutB_;
  using TensorRefB = TensorRef<ElementB const, LayoutB>;
  using ElementC = ElementC_;
  using LayoutC = layout::ColumnMajor;
  using TensorRefC = TensorRef<ElementC const, LayoutC>;
  using TensorRefD = TensorRef<ElementC, LayoutC>;
  using ElementAccumulator = ElementAccumulator_;
  using OperatorClass = OperatorClass_;
  using ArchTag = ArchTag_;
  using ThreadblockShape = ThreadblockShape_;
  using WarpShape = WarpShape_;
  using InstructionShape = InstructionShape_;
  using EpilogueOutputOp = EpilogueOutputOp_;
  using ThreadblockSwizzle = ThreadblockSwizzle_;
  using Operator = Operator_;
  static int const kStages = Stages;
  static int const kAlignmentA = AlignmentA;
  static int const kAlignmentB = AlignmentB;
  static ComplexTransform const kTransformA = ComplexTransform::kNone;
  static ComplexTransform const kTransformB = ComplexTransform::kNone;
  static bool const kSplitKSerial = SplitKSerial;
  static bool const kIsASparse = false;

  using UnderlyingOperator = EllGemm< 
    ElementB,
    typename layout::LayoutTranspose<LayoutB>::type,
    ElementA,
    typename layout::LayoutTranspose<LayoutA>::type,
    ElementC,
    layout::RowMajor,    
    ElementAccumulator,
    OperatorClass,
    ArchTag,
    ThreadblockShape,
    WarpShape,
    InstructionShape,
    EpilogueOutputOp,
    ThreadblockSwizzle,
    Stages,
    kAlignmentB,
    kAlignmentA,
    SplitKSerial,
    Operator,
    kIsASparse
  >;

  using UnderlyingArguments = typename UnderlyingOperator::Arguments;
  using GemmKernel = typename UnderlyingOperator::GemmKernel;
  static int const kAlignmentC = UnderlyingOperator::kAlignmentC;

  /// Argument structure
  struct Arguments {

    //
    // Data members
    //

    GemmCoord problem_size;
    TensorRef<ElementA const, LayoutA> ref_A;
    TensorRef<ElementB const, LayoutB> ref_B;
    TensorRef<ElementC const, LayoutC> ref_C;
    TensorRef<ElementC, LayoutC> ref_D;
    const int* ell_idx;
    int ell_ncol;
    int ell_blocksize;
    int ell_base_idx;
    typename EpilogueOutputOp::Params epilogue;
    int split_k_slices;

    //
    // Methods
    //

    /// Default ctor
    CUTLASS_HOST_DEVICE
    Arguments() { }

    /// Constructs an Arguments structure 
    CUTLASS_HOST_DEVICE
    Arguments(
      GemmCoord problem_size_,
      TensorRef<ElementA const, LayoutA> ref_A_,
      TensorRef<ElementB const, LayoutB> ref_B_,
      TensorRef<ElementC const, LayoutC> ref_C_,
      TensorRef<ElementC, LayoutC> ref_D_,
      const int* ell_idx_,
      int ell_ncol_,
      int ell_blocksize_,
      int ell_base_idx_,
      typename EpilogueOutputOp::Params epilogue_ = 
        typename EpilogueOutputOp::Params(),
      int split_k_slices = 1
    ):
      problem_size(problem_size_),
      ref_A(ref_A_),
      ref_B(ref_B_),
      ref_C(ref_C_),
      ref_D(ref_D_),
      ell_idx(ell_idx_),
      ell_ncol(ell_ncol_),
      ell_blocksize(ell_blocksize_),
      ell_base_idx(ell_base_idx_),
      epilogue(epilogue_),
      split_k_slices(split_k_slices) { }
  };

private:

  UnderlyingOperator underlying_operator_;

public:

  /// Constructs the GEMM.
  EllGemm() { }

  /// Helper to construct a transposed equivalent for the underying GEMM operator
  static UnderlyingArguments to_underlying_arguments(Arguments const &args) {
    return UnderlyingArguments(
      {args.problem_size.n(), args.problem_size.m(), args.problem_size.k()},
      {args.ref_B.data(), args.ref_B.stride(0)},
      {args.ref_A.data(), args.ref_A.stride(0)},
      {args.ref_C.data(), args.ref_C.stride(0)},
      {args.ref_D.data(), args.ref_D.stride(0)},
      args.ell_idx,
      args.ell_ncol,
      args.ell_blocksize,
      args.ell_base_idx,
      args.epilogue,
      args.split_k_slices
    );
  }

  /// Determines whether the GEMM can execute the given problem.
  static Status can_implement(Arguments const &args) {

    return UnderlyingOperator::can_implement(to_underlying_arguments(args));
  }

  /// Gets the workspace size
  static size_t get_workspace_size(Arguments const &args) {
    
    size_t bytes = 0;

    // Determine grid shape
    ThreadblockSwizzle threadblock_swizzle;

    cutlass::gemm::GemmCoord tiled_shape = threadblock_swizzle.get_tiled_shape(
      args.problem_size, 
      {ThreadblockShape::kM, args.ell_blocksize, ThreadblockShape::kK},
      args.split_k_slices);
    
    tiled_shape.n() *= (args.ell_blocksize + ThreadblockShape::kN - 1 ) / ThreadblockShape::kN;

    if (kSplitKSerial && args.split_k_slices > 1) {

      bytes += sizeof(int) * size_t(tiled_shape.m()) * size_t(tiled_shape.n());
    }

    return bytes;
  }

  Status set(Arguments const &args, cutlass::gemm::GemmCoord const &grid_shape, void *workspace){
    // Initialize the Params structure
    return underlying_operator_.set(to_underlying_arguments(args), grid_shape, workspace);
  }

  /// Initializes GEMM state from arguments.
  Status initialize(Arguments const &args, void *workspace = nullptr, cudaStream_t stream = nullptr) {

    // Determine grid shape
    ThreadblockSwizzle threadblock_swizzle;

    cutlass::gemm::GemmCoord grid_shape = threadblock_swizzle.get_tiled_shape(
      {args.problem_size.n(), args.problem_size.m(), args.problem_size.k()}, 
      {ThreadblockShape::kM, args.ell_blocksize, ThreadblockShape::kK},
      args.split_k_slices);
    
    grid_shape.n() *= (args.ell_blocksize + ThreadblockShape::kN - 1 ) / ThreadblockShape::kN;

    if (kSplitKSerial) {
      if (args.split_k_slices > 1) {
        if (!workspace) {
          return Status::kErrorWorkspaceNull;
        }

        size_t bytes = get_workspace_size(args);
      
        cudaError_t result = cudaMemsetAsync(workspace, 0, bytes, stream);

        if (result != cudaSuccess) {
          return Status::kErrorInternal;
        }
      }
    }
    else {

      if (args.split_k_slices > 1) {
        return Status::kErrorInvalidProblem;
      }
    }

    // Initialize the Params structure
    set(args, grid_shape, workspace);

    return Status::kSuccess;
  }

  /// Lightweight update given a subset of arguments
  Status update(Arguments const &args, void *workspace = nullptr) {

    return underlying_operator_.update(to_underlying_arguments(args), workspace);
  }

  /// Runs the kernel using initialized state.
  Status run(cudaStream_t stream = nullptr) {

    return underlying_operator_.run(stream);
  }

  /// Runs the kernel using initialized state.
  Status operator()(cudaStream_t stream = nullptr) {
    return run(stream);
  }

  /// Runs the kernel using initialized state.
  Status operator()(
    Arguments const &args, 
    void *workspace = nullptr, 
    cudaStream_t stream = nullptr) {
    
    Status status = initialize(args, workspace, stream);
    
    if (status == Status::kSuccess) {
      status = run(stream);
    }

    return status;
  }
};

////////////////////////////////////////////////////////////////////////////////

} // namespace device
} // namespace gemm
} // namespace cutlass

////////////////////////////////////////////////////////////////////////////////
