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/*! \file
    \brief Tests for device-wide GEMM interface
*/

#include <iostream>

#include "../../common/cutlass_unit_test.h"

#include "cutlass/cutlass.h"
#include "cutlass/epilogue/thread/linear_combination.h"
#include "cutlass/reduction/kernel/reduce_split_k.h"
#include "cutlass/reduction/thread/reduction_operators.h"

#include "cutlass/util/host_tensor.h"
#include "cutlass/util/reference/host/gemm.h"
#include "cutlass/util/reference/host/tensor_compare.h"
#include "cutlass/util/reference/host/tensor_copy.h"
#include "cutlass/util/reference/host/tensor_fill.h"
#include "cutlass/util/reference/host/tensor_norm.h"
#include "cutlass/util/tensor_view_io.h"

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

namespace test {
namespace reduction {

template <typename ReductionKernel>
__global__ void kernel_reduce_splitk(typename ReductionKernel::Params params) {
    __shared__ typename ReductionKernel::SharedStorage shared_storage;

    ReductionKernel reduction_op;

    reduction_op(params, shared_storage);
}

template <typename ReductionKernel>
class ReduceSplitKTestbed {
public:
    using ElementAccumulator = typename ReductionKernel::ElementAccumulator;
    using ElementWorkspace = typename ReductionKernel::ElementWorkspace;
    using ElementOutput = typename ReductionKernel::ElementOutput;
    using Layout = cutlass::layout::RowMajor;

public:
    cutlass::Distribution::Kind distribution_workspace;
    cutlass::Distribution::Kind distribution_source;
    uint64_t seed;

public:
    /// Ctor
    ReduceSplitKTestbed(cutlass::Distribution::Kind distribution_workspace =
                                cutlass::Distribution::Uniform,
                        cutlass::Distribution::Kind distribution_source =
                                cutlass::Distribution::Uniform,
                        uint64_t seed = 2019)
            : distribution_workspace(distribution_workspace),
              distribution_source(distribution_source),
              seed(seed) {}

    /// Helper to initialize a tensor view
    template <typename Element, typename Layout>
    bool initialize_tensor(cutlass::TensorView<Element, Layout> view,
                           cutlass::Distribution::Kind dist_kind,
                           uint64_t seed) {
        if (dist_kind == cutlass::Distribution::Uniform) {
            cutlass::reference::host::TensorFillRandomUniform(view, seed, 8, -8,
                                                              0);
        } else if (dist_kind == cutlass::Distribution::Gaussian) {
            cutlass::reference::host::TensorFillRandomGaussian(view, seed, 0,
                                                               0.5, -1);
        } else if (dist_kind == cutlass::Distribution::Identity) {
            cutlass::reference::host::TensorFillIdentity(view);
        } else if (dist_kind == cutlass::Distribution::Sequential) {
            cutlass::reference::host::BlockFillSequential(view.data(),
                                                          view.capacity());
        } else {
            // TODO: Implement the rest
            EXPECT_TRUE(false) << "Not implemented";
            return false;
        }

        return true;
    }

    /// Runs a single problem size
    bool run(cutlass::MatrixCoord problem_size, int partitions,
             ElementAccumulator alpha = 1, ElementAccumulator beta = 0) {
        cutlass::HostTensor<ElementWorkspace, Layout> workspace(
                {problem_size.row() * partitions, problem_size.column()});

        cutlass::HostTensor<ElementOutput, Layout> source(problem_size);
        cutlass::HostTensor<ElementOutput, Layout> destination(problem_size);
        cutlass::HostTensor<ElementOutput, Layout> destination_reference(
                problem_size, false);

        //
        // Initialize
        //
        initialize_tensor(workspace.host_view(), distribution_workspace, seed);
        initialize_tensor(source.host_view(), distribution_source, seed + 23);

        cutlass::reference::host::TensorFill(destination.host_view());

        workspace.sync_device();
        source.sync_device();
        destination.sync_device();

        //
        // Launch reduction kernel
        //

        dim3 block = ReductionKernel::block_shape();
        dim3 grid = ReductionKernel::grid_shape(problem_size);

        typename ReductionKernel::Params params(
                problem_size, partitions,
                problem_size.row() * problem_size.column(),
                workspace.device_ref(), destination.device_ref(),
                source.device_ref(), {alpha, beta});

        test::reduction::kernel_reduce_splitk<ReductionKernel>
                <<<grid, block>>>(params);

        cudaError_t result = cudaDeviceSynchronize();

        EXPECT_EQ(result, cudaSuccess)
                << "CUDA error: " << cudaGetErrorString(result);

        destination.sync_host();

        //
        // Compute reference
        //

        for (int m = 0; m < problem_size.row(); ++m) {
            for (int n = 0; n < problem_size.column(); ++n) {
                ElementAccumulator accum = 0;

                for (int k = 0; k < partitions; ++k) {
                    accum += ElementAccumulator(
                            workspace.at({m + k * problem_size.row(), n}));
                }

                ElementAccumulator c = ElementAccumulator(source.at({m, n}));

                destination_reference.at({m, n}) =
                        ElementOutput(accum * alpha + beta * c);
            }
        }

        //
        // Compare
        //

        EXPECT_GT(cutlass::reference::host::TensorNorm(destination.host_view()),
                  0);
        EXPECT_GT(cutlass::reference::host::TensorNorm(
                          destination_reference.host_view()),
                  0);

        bool passed = cutlass::reference::host::TensorEquals(
                destination.host_view(), destination_reference.host_view());

        EXPECT_TRUE(passed) << "Workspace =\n"
                            << workspace.host_view() << "\n\n"
                            << "\n"
                            << "Reference =\n"
                            << destination_reference.host_view() << "\n\n"
                            << "Computed =\n"
                            << destination.host_view() << "\n";

        return passed;
    }

    /// Runs through a variety of test cases
    bool run_all() {
        cutlass::MatrixCoord problem_sizes[] = {
                {8, 8},
                {136, 72},
                {248, 232},
        };

        int partition_counts[] = {1, 3, 4, 5, 11};

        bool passed = false;

        for (cutlass::MatrixCoord problem : problem_sizes) {
            for (int partitions : partition_counts) {
                passed = run(problem, partitions);
                if (!passed) {
                    return false;
                }
            }
        }

        return passed;
    }
};

}  // namespace reduction
}  // namespace test

/////////////////////////////////////////////////////////////////////////////////////////////////
//
// Strictly F32 data
//
TEST(Reduction_ReduceSplitK, f32_f32_f32_1_1x32) {
    using ElementWorkspace = float;
    using ElementAccumulator = float;
    using ElementOutput = float;
    int const kN = 1;
    using Shape = cutlass::MatrixShape<1, 32>;

    using OutputOp = cutlass::epilogue::thread::LinearCombination<
            ElementOutput, kN, ElementAccumulator, ElementAccumulator>;

    using ReductionOp =
            cutlass::reduction::thread::ReduceAdd<ElementAccumulator,
                                                  ElementWorkspace, kN>;

    using ReductionKernel =
            cutlass::reduction::kernel::ReduceSplitK<Shape, OutputOp,
                                                     ReductionOp>;

    test::reduction::ReduceSplitKTestbed<ReductionKernel> testbed;

    EXPECT_TRUE(testbed.run_all());
}

/////////////////////////////////////////////////////////////////////////////////////////////////
//
// Vectorized access
//
TEST(Reduction_ReduceSplitK, f32_f32_f32_2_4x64) {
    using ElementWorkspace = float;
    using ElementAccumulator = float;
    using ElementOutput = float;
    int const kN = 2;
    using Shape = cutlass::MatrixShape<4, 64>;

    using OutputOp = cutlass::epilogue::thread::LinearCombination<
            ElementOutput, kN, ElementAccumulator, ElementAccumulator>;

    using ReductionOp =
            cutlass::reduction::thread::ReduceAdd<ElementAccumulator,
                                                  ElementWorkspace, kN>;

    using ReductionKernel =
            cutlass::reduction::kernel::ReduceSplitK<Shape, OutputOp,
                                                     ReductionOp>;

    test::reduction::ReduceSplitKTestbed<ReductionKernel> testbed;

    EXPECT_TRUE(testbed.run_all());
}

/////////////////////////////////////////////////////////////////////////////////////////////////
//
// Vectorized access
//
TEST(Reduction_ReduceSplitK, f32_f32_f16_2_4x64) {
    using ElementWorkspace = float;
    using ElementAccumulator = float;
    using ElementOutput = cutlass::half_t;
    int const kN = 2;
    using Shape = cutlass::MatrixShape<4, 64>;

    using OutputOp = cutlass::epilogue::thread::LinearCombination<
            ElementOutput, kN, ElementAccumulator, ElementAccumulator>;

    using ReductionOp =
            cutlass::reduction::thread::ReduceAdd<ElementAccumulator,
                                                  ElementWorkspace, kN>;

    using ReductionKernel =
            cutlass::reduction::kernel::ReduceSplitK<Shape, OutputOp,
                                                     ReductionOp>;

    test::reduction::ReduceSplitKTestbed<ReductionKernel> testbed;

    EXPECT_TRUE(testbed.run_all());
}

/////////////////////////////////////////////////////////////////////////////////////////////////
//
// Vectorized access
//
TEST(Reduction_ReduceSplitK, f32_f32_f16_8_4x64) {
    using ElementWorkspace = float;
    using ElementAccumulator = float;
    using ElementOutput = cutlass::half_t;
    int const kN = 8;
    using Shape = cutlass::MatrixShape<4, 64>;

    using OutputOp = cutlass::epilogue::thread::LinearCombination<
            ElementOutput, kN, ElementAccumulator, ElementAccumulator>;

    using ReductionOp =
            cutlass::reduction::thread::ReduceAdd<ElementAccumulator,
                                                  ElementWorkspace, kN>;

    using ReductionKernel =
            cutlass::reduction::kernel::ReduceSplitK<Shape, OutputOp,
                                                     ReductionOp>;

    test::reduction::ReduceSplitKTestbed<ReductionKernel> testbed;

    EXPECT_TRUE(testbed.run_all());
}

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