TheRock/rocm-libraries/projects/rocrand/test/internal/test_rocrand_discrete.cpp

// Copyright (c) 2017-2025 Advanced Micro Devices, Inc. All rights reserved.
//
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//
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
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// THE SOFTWARE.

#include <gtest/gtest.h>
#include <stdio.h>

#include "test_common.hpp"
#include "test_rocrand_common.hpp"

#include <algorithm>
#include <numeric>
#include <random>

#include <rocrand/rocrand_discrete.h>
#include <rocrand/rocrand_mtgp32_11213.h>
#include <vector>

#include <hip/hip_runtime.h>

struct GlobalSizes
{
    static constexpr size_t items_per_thread = 256;
    static constexpr size_t block_size       = 32;
    static constexpr size_t items_per_block  = items_per_thread * block_size;
    static constexpr size_t grid_size        = 1234;
    static constexpr size_t size             = grid_size * items_per_block;
};

using DiscreteDataType
    = ::testing::Types<double, unsigned int, unsigned long, unsigned long long int>;

template<typename DT>
class InternalDiscreteDistributionTests : public ::testing::Test
{
public:
    using T = DT;
};

TYPED_TEST_SUITE(InternalDiscreteDistributionTests, DiscreteDataType);

template<typename T, class DiscreteWrapper>
__global__
void internal_discrete_kernel(T*                                device_input,
                              unsigned int*                     device_output,
                              rocrand_discrete_distribution_st& dis)
{
    const size_t items_per_block = GlobalSizes::items_per_thread * GlobalSizes::block_size;
    const size_t offset
        = (items_per_block * blockIdx.x) + (GlobalSizes::items_per_thread * threadIdx.x);

    for(size_t i = 0; i < GlobalSizes::items_per_thread; i++)
    {
        device_output[offset + i] = DiscreteWrapper{}(device_input[offset + i], dis);
    }
}

template<typename T, class DiscreteWrapper>
void run_internal_discrete_tests()
{
    std::vector<std::vector<double>> all_distributions = {
        {10, 10, 10, 10},
        {1, 2, 3, 4, 5, 6, 5, 4, 3, 2, 1},
        {1234, 1677, 1519, 1032, 561, 254, 98, 33, 10, 2},
        {1, 2, 8, 4, 3, 2, 1}
    };

    std::random_device rd;
    std::mt19937       gen(rd());

    T*            host_input  = new T[GlobalSizes::size];
    unsigned int* host_output = new unsigned int[GlobalSizes::size];

    // Check for different types of data input and generate the input data
    if constexpr(std::is_same_v<T, double>)
    {
        std::uniform_real_distribution<double> dis(0, 1);
        for(size_t i = 0; i < GlobalSizes::size; i++)
            host_input[i] = dis(gen);
    }
    else if constexpr(std::is_same_v<T, unsigned long> || std::is_same_v<T, unsigned int>)
    {
        std::uniform_int_distribution<T> dis(0, std::numeric_limits<unsigned int>::max());
        for(size_t i = 0; i < GlobalSizes::size; i++)
            host_input[i] = dis(gen);
    }
    else
    {
        std::uniform_int_distribution<T> dis(0, std::numeric_limits<T>::max());
        for(size_t i = 0; i < GlobalSizes::size; i++)
            host_input[i] = dis(gen);
    }

    T*            device_input;
    unsigned int* device_output;

    HIP_CHECK(hipMalloc(&device_input, sizeof(T) * GlobalSizes::size));
    HIP_CHECK(hipMalloc(&device_output, sizeof(unsigned int) * GlobalSizes::size));

    HIP_CHECK(
        hipMemcpy(device_input, host_input, sizeof(T) * GlobalSizes::size, hipMemcpyHostToDevice));

    // Generate different discrete distributions and check them against expected
    for(std::vector<double> distribution : all_distributions)
    {
        // Getting expected Results
        double              sum = std::accumulate(distribution.begin(), distribution.end(), 0);
        std::vector<double> expected_prob(distribution.size());
        for(size_t i = 0; i < distribution.size(); i++)
            expected_prob[i] = distribution[i] / sum;

        // Creating the discrete distribution
        rocrand_discrete_distribution discrete_distribution;
        ROCRAND_CHECK(rocrand_create_discrete_distribution(expected_prob.data(),
                                                           expected_prob.size(),
                                                           0,
                                                           &discrete_distribution));

        internal_discrete_kernel<T, DiscreteWrapper>
            <<<dim3(GlobalSizes::grid_size), dim3(GlobalSizes::block_size), 0, 0>>>(
                device_input,
                device_output,
                *discrete_distribution);

        HIP_CHECK(hipMemcpy(host_output,
                            device_output,
                            sizeof(unsigned int) * GlobalSizes::size,
                            hipMemcpyDeviceToHost));

        std::vector<double> histogram(distribution.size());

        // Calculating the actual results
        for(size_t i = 0; i < GlobalSizes::size; i++)
            histogram[host_output[i]]++;

        std::vector<double> actual_prob(distribution.size());
        for(size_t i = 0; i < actual_prob.size(); i++)
            actual_prob[i] = histogram[i] / static_cast<double>(GlobalSizes::size);

        ASSERT_TRUE(ks_test_2(expected_prob, actual_prob));

        ROCRAND_CHECK(rocrand_destroy_discrete_distribution(discrete_distribution));
    }

    delete[] host_input;
    delete[] host_output;

    HIP_CHECK(hipFree(device_input));
    HIP_CHECK(hipFree(device_output));
}

template<typename T>
struct internal_discrete_alias
{
    __device__
    auto operator()(T val, rocrand_discrete_distribution_st& dis)
    {
        return rocrand_device::detail::discrete_alias(val, dis);
    }
};

template<typename T>
struct internal_discrete_cdf
{
    __device__
    auto operator()(T val, rocrand_discrete_distribution_st& dis)
    {
        return rocrand_device::detail::discrete_cdf(val, dis);
    }
};

TYPED_TEST(InternalDiscreteDistributionTests, InternalDiscreteAliasTest)
{
    using T = typename TestFixture::T;

    run_internal_discrete_tests<T, internal_discrete_alias<T>>();
}

TYPED_TEST(InternalDiscreteDistributionTests, InternalDiscreteCDFTest)
{
    using T = typename TestFixture::T;

    run_internal_discrete_tests<T, internal_discrete_cdf<T>>();
}

template<class RocRandPrngType>
__global__
void block_wide_external_discrete_kernel(RocRandPrngType*                  states,
                                         unsigned int*                     device_output,
                                         rocrand_discrete_distribution_st& dis,
                                         size_t                            items_per_thread,
                                         size_t                            block_size)
{
    const size_t items_per_block = items_per_thread * block_size;
    const size_t offset = (items_per_block * blockIdx.x) + (items_per_thread * threadIdx.x);

    for(size_t i = 0; i < items_per_thread; i++)
    {
        __shared__
        RocRandPrngType state;
        if(threadIdx.x == 0)
            state = states[blockIdx.x];
        __syncthreads();

        device_output[offset + i] = rocrand_discrete(&state, &dis);

        if(threadIdx.x == 0)
            states[blockIdx.x] = state;
        __syncthreads();
    }
}

template<class RocRandPrngType>
__global__
void external_discrete_kernel(RocRandPrngType*                  states,
                              unsigned int*                     device_output,
                              rocrand_discrete_distribution_st& dis,
                              size_t                            items_per_thread,
                              size_t                            block_size)
{
    const size_t items_per_block = items_per_thread * block_size;
    const size_t offset = (items_per_block * blockIdx.x) + (items_per_thread * threadIdx.x);

    for(size_t i = 0; i < items_per_thread; i++)
    {
        auto local_state          = states[offset + i];
        device_output[offset + i] = rocrand_discrete(&local_state, &dis);
        states[offset + i]        = local_state;
    }
}

template<bool block_wide, class PrngState>
void run_external_discrete_tests(PrngState& device_states,
                                 size_t     items_per_thread = GlobalSizes::items_per_thread,
                                 size_t     block_size       = GlobalSizes::block_size,
                                 size_t     grid_size        = GlobalSizes::grid_size,
                                 size_t     size             = GlobalSizes::size)
{

    std::vector<std::vector<double>> all_distributions = {
        {10, 10, 10, 10},
        {1, 2, 3, 4, 5, 6, 5, 4, 3, 2, 1},
        {1234, 1677, 1519, 1032, 561, 254, 98, 33, 10, 2},
        {1, 2, 8, 4, 3, 2, 1}
    };

    unsigned int* host_output = new unsigned int[size];
    unsigned int* device_output;
    HIP_CHECK(hipMalloc(&device_output, sizeof(unsigned int) * size));

    for(std::vector<double> distribution : all_distributions)
    {

        // Getting expected Results
        double              sum = std::accumulate(distribution.begin(), distribution.end(), 0);
        std::vector<double> expected_prob(distribution.size());
        for(size_t i = 0; i < distribution.size(); i++)
            expected_prob[i] = distribution[i] / sum;

        // Creating the discrete distribution
        rocrand_discrete_distribution discrete_distribution;
        ROCRAND_CHECK(rocrand_create_discrete_distribution(expected_prob.data(),
                                                           expected_prob.size(),
                                                           0,
                                                           &discrete_distribution));

        if constexpr(block_wide)
        {
            hipLaunchKernelGGL(HIP_KERNEL_NAME(block_wide_external_discrete_kernel),
                               dim3(grid_size),
                               dim3(block_size),
                               0,
                               0,
                               device_states,
                               device_output,
                               *discrete_distribution,
                               items_per_thread,
                               block_size);
        }
        else
        {
            hipLaunchKernelGGL(HIP_KERNEL_NAME(external_discrete_kernel),
                               dim3(grid_size),
                               dim3(block_size),
                               0,
                               0,
                               device_states,
                               device_output,
                               *discrete_distribution,
                               items_per_thread,
                               block_size);
        }

        HIP_CHECK(hipMemcpy(host_output,
                            device_output,
                            sizeof(unsigned int) * size,
                            hipMemcpyDeviceToHost));
        std::vector<double> histogram(distribution.size());

        // Calculating the actual results
        for(size_t i = 0; i < size; i++)
            histogram[host_output[i]]++;

        std::vector<double> actual_prob(distribution.size());
        for(size_t i = 0; i < actual_prob.size(); i++)
            actual_prob[i] = histogram[i] / static_cast<double>(size);

        ASSERT_TRUE(ks_test_2(expected_prob, actual_prob));
        ROCRAND_CHECK(rocrand_destroy_discrete_distribution(discrete_distribution));
    }

    delete[] host_output;
    HIP_CHECK(hipFree(device_output));
}

template<class RocRandPrngType>
__global__
void init_rocrand_states_kernel(RocRandPrngType* states)
{
    constexpr size_t items_per_block = GlobalSizes::items_per_thread * GlobalSizes::block_size;
    const size_t     offset
        = (items_per_block * blockIdx.x) + (GlobalSizes::items_per_thread * threadIdx.x);

    for(size_t i = 0; i < GlobalSizes::items_per_thread; i++)
    {
        rocrand_init(static_cast<unsigned int>(123456 ^ i), offset + i, 0, &states[offset + i]);
    }
}

template<class RocRandPrngType>
__global__
void init_rocrand_states_kernel4(RocRandPrngType* states)
{
    constexpr size_t items_per_block = GlobalSizes::items_per_thread * GlobalSizes::block_size;
    const size_t     offset
        = (items_per_block * blockIdx.x) + (GlobalSizes::items_per_thread * threadIdx.x);

    for(size_t i = 0; i < GlobalSizes::items_per_thread; i++)
    {
        rocrand_init(uint4{static_cast<unsigned int>((123456 ^ i)),
                           static_cast<unsigned int>((123456 ^ i) << 1),
                           static_cast<unsigned int>((123456 ^ i) << 2),
                           static_cast<unsigned int>((123456 ^ i) << 3)},
                     offset + i,
                     0,
                     &states[offset + i]);
    }
}

TEST(ExternalDiscreteDistributionTests, Philox4x32_10Test)
{
    // Initialize the prng state
    rocrand_state_philox4x32_10* device_states;
    HIP_CHECK(hipMalloc(&device_states, sizeof(rocrand_state_philox4x32_10) * GlobalSizes::size));

    struct f
    {
        __device__
        static void init(size_t index, size_t offset, rocrand_state_philox4x32_10* state)
        {
            rocrand_init((123456 ^ index), offset + index, 0, state);
        }
    };

    init_rocrand_states_kernel<<<dim3(GlobalSizes::grid_size),
                                 dim3(GlobalSizes::block_size),
                                 0,
                                 0>>>(device_states);

    run_external_discrete_tests<false>(device_states);

    HIP_CHECK(hipFree(device_states));
}

TEST(ExternalDiscreteDistributionTests, Mrg31k3pTest)
{
    // Initialize the prng state
    rocrand_state_mrg31k3p* device_states;
    HIP_CHECK(hipMalloc(&device_states, sizeof(rocrand_state_mrg31k3p) * GlobalSizes::size));

    struct f
    {
        __device__
        static void init(size_t index, size_t offset, rocrand_state_mrg31k3p* state)
        {
            rocrand_init((123456 ^ index), offset + index, 0, state);
        }
    };

    init_rocrand_states_kernel<<<dim3(GlobalSizes::grid_size),
                                 dim3(GlobalSizes::block_size),
                                 0,
                                 0>>>(device_states);

    run_external_discrete_tests<false>(device_states);

    HIP_CHECK(hipFree(device_states));
}

TEST(ExternalDiscreteDistributionTests, Mrg32k3aTest)
{
    // Initialize the prng state
    rocrand_state_mrg32k3a* device_states;
    HIP_CHECK(hipMalloc(&device_states, sizeof(rocrand_state_mrg32k3a) * GlobalSizes::size));

    init_rocrand_states_kernel<<<dim3(GlobalSizes::grid_size),
                                 dim3(GlobalSizes::block_size),
                                 0,
                                 0>>>(device_states);

    run_external_discrete_tests<false>(device_states);

    HIP_CHECK(hipFree(device_states));
}

TEST(ExternalDiscreteDistributionTests, XorwowTest)
{
    // Initialize the prng state
    rocrand_state_xorwow* device_states;
    HIP_CHECK(hipMalloc(&device_states, sizeof(rocrand_state_xorwow) * GlobalSizes::size));

    init_rocrand_states_kernel<<<dim3(GlobalSizes::grid_size),
                                 dim3(GlobalSizes::block_size),
                                 0,
                                 0>>>(device_states);

    run_external_discrete_tests<false>(device_states);

    HIP_CHECK(hipFree(device_states));
}

TEST(ExternalDiscreteDistributionTests, Mtgp32Test)
{
    constexpr size_t items_per_thread = 1024;
    constexpr size_t block_size       = 256;
    constexpr size_t grid_size        = 12;
    constexpr size_t items_per_block  = block_size * items_per_thread;

    constexpr size_t      test_size = items_per_block * grid_size;
    rocrand_state_mtgp32* states;

    HIP_CHECK(hipMalloc(&states, sizeof(rocrand_state_mtgp32) * grid_size));
    rocrand_make_state_mtgp32(states, mtgp32dc_params_fast_11213, grid_size, 123456);
    HIP_CHECK(hipDeviceSynchronize());

    run_external_discrete_tests<true>(states, items_per_thread, block_size, grid_size, test_size);
    HIP_CHECK(hipFree(states));
}

TEST(ExternalDiscreteDistributionTests, Lfsr113Test)
{
    // Initialize the prng state
    rocrand_state_lfsr113* device_states;
    HIP_CHECK(hipMalloc(&device_states, sizeof(rocrand_state_lfsr113) * GlobalSizes::size));

    init_rocrand_states_kernel4<<<dim3(GlobalSizes::grid_size),
                                  dim3(GlobalSizes::block_size),
                                  0,
                                  0>>>(device_states);

    run_external_discrete_tests<false>(device_states);

    HIP_CHECK(hipFree(device_states));
}

TEST(ExternalDiscreteDistributionTests, Sobol32Test)
{
    // Initialize the prng state
    rocrand_state_sobol32* host_states = new rocrand_state_sobol32[GlobalSizes::size];
    const unsigned int*    directions;
    ROCRAND_CHECK(
        rocrand_get_direction_vectors32(&directions, ROCRAND_DIRECTION_VECTORS_32_JOEKUO6));

    // 640000 is the size of directions. This is to prevent overflow stuff
    for(size_t i = 0; i < GlobalSizes::size; i++)
        rocrand_init(directions, i % 640000, host_states + i);

    rocrand_state_sobol32* device_states;
    HIP_CHECK(hipMalloc(&device_states, sizeof(rocrand_state_sobol32) * GlobalSizes::size));
    HIP_CHECK(hipMemcpy(device_states,
                        host_states,
                        sizeof(rocrand_state_sobol32) * GlobalSizes::size,
                        hipMemcpyHostToDevice));

    run_external_discrete_tests<false>(device_states);

    delete[] host_states;
    HIP_CHECK(hipFree(device_states));
}

TEST(ExternalDiscreteDistributionTests, ScrambledSobol32Test)
{
    // Initialize the prng state
    rocrand_state_scrambled_sobol32* host_states
        = new rocrand_state_scrambled_sobol32[GlobalSizes::size];
    const unsigned int* directions;
    ROCRAND_CHECK(
        rocrand_get_direction_vectors32(&directions, ROCRAND_DIRECTION_VECTORS_32_JOEKUO6));

    // 640000 is the size of directions. This is to prevent overflow stuff
    for(size_t i = 0; i < GlobalSizes::size; i++)
        rocrand_init(directions, 123456 ^ i, i % 640000, host_states + i);

    rocrand_state_scrambled_sobol32* device_states;
    HIP_CHECK(
        hipMalloc(&device_states, sizeof(rocrand_state_scrambled_sobol32) * GlobalSizes::size));
    HIP_CHECK(hipMemcpy(device_states,
                        host_states,
                        sizeof(rocrand_state_scrambled_sobol32) * GlobalSizes::size,
                        hipMemcpyHostToDevice));

    run_external_discrete_tests<false>(device_states);

    delete[] host_states;
    HIP_CHECK(hipFree(device_states));
}

TEST(ExternalDiscreteDistributionTests, Sobol64Test)
{
    // Initialize the prng state
    rocrand_state_sobol64*    host_states = new rocrand_state_sobol64[GlobalSizes::size];
    const unsigned long long* directions;
    ROCRAND_CHECK(
        rocrand_get_direction_vectors64(&directions, ROCRAND_DIRECTION_VECTORS_64_JOEKUO6));

    // 1280000 is the size of directions. This is to prevent overflow stuff
    for(size_t i = 0; i < GlobalSizes::size; i++)
        rocrand_init(directions, i % 1280000, host_states + i);

    rocrand_state_sobol64* device_states;
    HIP_CHECK(hipMalloc(&device_states, sizeof(rocrand_state_sobol64) * GlobalSizes::size));
    HIP_CHECK(hipMemcpy(device_states,
                        host_states,
                        sizeof(rocrand_state_sobol64) * GlobalSizes::size,
                        hipMemcpyHostToDevice));

    run_external_discrete_tests<false>(device_states);

    delete[] host_states;
    HIP_CHECK(hipFree(device_states));
}

TEST(ExternalDiscreteDistributionTests, ScrambledSobol64Test)
{
    // Initialize the prng state
    rocrand_state_scrambled_sobol64* host_states
        = new rocrand_state_scrambled_sobol64[GlobalSizes::size];
    const unsigned long long* directions;
    ROCRAND_CHECK(
        rocrand_get_direction_vectors64(&directions, ROCRAND_DIRECTION_VECTORS_64_JOEKUO6));

    // 1280000 is the size of directions. This is to prevent overflow stuff
    for(size_t i = 0; i < GlobalSizes::size; i++)
        rocrand_init(directions, 123456 ^ i, i % 1280000, host_states + i);

    rocrand_state_scrambled_sobol64* device_states;
    HIP_CHECK(
        hipMalloc(&device_states, sizeof(rocrand_state_scrambled_sobol64) * GlobalSizes::size));
    HIP_CHECK(hipMemcpy(device_states,
                        host_states,
                        sizeof(rocrand_state_scrambled_sobol64) * GlobalSizes::size,
                        hipMemcpyHostToDevice));

    run_external_discrete_tests<false>(device_states);

    delete[] host_states;
    HIP_CHECK(hipFree(device_states));
}

TEST(ExternalDiscreteDistributionTests, Threefry2x32_20Test)
{
    // Initialize the prng state
    rocrand_state_threefry2x32_20* device_states;
    HIP_CHECK(hipMalloc(&device_states, sizeof(rocrand_state_threefry2x32_20) * GlobalSizes::size));

    init_rocrand_states_kernel<<<dim3(GlobalSizes::grid_size),
                                 dim3(GlobalSizes::block_size),
                                 0,
                                 0>>>(device_states);

    run_external_discrete_tests<false>(device_states);

    HIP_CHECK(hipFree(device_states));
}

TEST(ExternalDiscreteDistributionTests, Threefry2x64_20Test)
{
    // Initialize the prng state
    rocrand_state_threefry2x64_20* device_states;
    HIP_CHECK(hipMalloc(&device_states, sizeof(rocrand_state_threefry2x64_20) * GlobalSizes::size));

    init_rocrand_states_kernel<<<dim3(GlobalSizes::grid_size),
                                 dim3(GlobalSizes::block_size),
                                 0,
                                 0>>>(device_states);

    run_external_discrete_tests<false>(device_states);

    HIP_CHECK(hipFree(device_states));
}

TEST(ExternalDiscreteDistributionTests, Threefry4x32_20Test)
{
    // Initialize the prng state
    rocrand_state_threefry4x32_20* device_states;
    HIP_CHECK(hipMalloc(&device_states, sizeof(rocrand_state_threefry4x32_20) * GlobalSizes::size));

    init_rocrand_states_kernel<<<dim3(GlobalSizes::grid_size),
                                 dim3(GlobalSizes::block_size),
                                 0,
                                 0>>>(device_states);

    run_external_discrete_tests<false>(device_states);

    HIP_CHECK(hipFree(device_states));
}

TEST(ExternalDiscreteDistributionTests, Threefry4x64_20Test)
{
    // Initialize the prng state
    rocrand_state_threefry4x64_20* device_states;
    HIP_CHECK(hipMalloc(&device_states, sizeof(rocrand_state_threefry4x64_20) * GlobalSizes::size));

    init_rocrand_states_kernel<<<dim3(GlobalSizes::grid_size),
                                 dim3(GlobalSizes::block_size),
                                 0,
                                 0>>>(device_states);

    run_external_discrete_tests<false>(device_states);

    HIP_CHECK(hipFree(device_states));
}

template<size_t items_per_thread, size_t block_size>
__global__
void uint4_kernel(rocrand_state_philox4x32_10*      states,
                  uint4*                            device_output,
                  rocrand_discrete_distribution_st& dis)
{
    const size_t items_per_block = items_per_thread * block_size;
    const size_t offset = (items_per_block * blockIdx.x) + (items_per_thread * threadIdx.x);

    for(size_t i = 0; i < items_per_thread; i++)
    {
        auto local_state          = states[offset + i];
        device_output[offset + i] = rocrand_discrete4(&local_state, &dis);
        states[offset + i]        = local_state;
    }
}

TEST(ExternalDiscreteDistributionTests, Philox4x32_10WithUIN4OutputTest)
{
    // Initialize the prng state
    rocrand_state_philox4x32_10* device_states;
    HIP_CHECK(hipMalloc(&device_states, sizeof(rocrand_state_philox4x32_10) * GlobalSizes::size));

    init_rocrand_states_kernel<<<dim3(GlobalSizes::grid_size),
                                 dim3(GlobalSizes::block_size),
                                 0,
                                 0>>>(device_states);

    std::vector<std::vector<double>> all_distributions = {
        {10, 10, 10, 10},
        {1, 2, 3, 4, 5, 6, 5, 4, 3, 2, 1},
        {1234, 1677, 1519, 1032, 561, 254, 98, 33, 10, 2},
        {1, 2, 8, 4, 3, 2, 1}
    };

    uint4* host_output = new uint4[GlobalSizes::size];
    uint4* device_output;
    HIP_CHECK(hipMalloc(&device_output, sizeof(uint4) * GlobalSizes::size));

    for(std::vector<double> distribution : all_distributions)
    {

        // Getting expected Results
        double              sum = std::accumulate(distribution.begin(), distribution.end(), 0);
        std::vector<double> expected_prob(distribution.size());
        for(size_t i = 0; i < distribution.size(); i++)
            expected_prob[i] = distribution[i] / sum;

        // Creating the discrete distribution
        rocrand_discrete_distribution discrete_distribution;
        ROCRAND_CHECK(rocrand_create_discrete_distribution(expected_prob.data(),
                                                           expected_prob.size(),
                                                           0,
                                                           &discrete_distribution));

        hipLaunchKernelGGL(
            HIP_KERNEL_NAME(uint4_kernel<GlobalSizes::items_per_thread, GlobalSizes::block_size>),
            dim3(GlobalSizes::grid_size),
            dim3(GlobalSizes::block_size),
            0,
            0,
            device_states,
            device_output,
            *discrete_distribution);

        HIP_CHECK(hipMemcpy(host_output,
                            device_output,
                            sizeof(uint4) * GlobalSizes::size,
                            hipMemcpyDeviceToHost));
        std::vector<double> histogram(distribution.size());

        // Calculating the actual results
        for(size_t i = 0; i < GlobalSizes::size; i++)
        {
            histogram[host_output[i].w]++;
            histogram[host_output[i].x]++;
            histogram[host_output[i].y]++;
            histogram[host_output[i].z]++;
        }

        std::vector<double> actual_prob(distribution.size());
        for(size_t i = 0; i < actual_prob.size(); i++)
            actual_prob[i] = histogram[i] / static_cast<double>(GlobalSizes::size * 4);

        ASSERT_TRUE(ks_test_2(expected_prob, actual_prob));
        ROCRAND_CHECK(rocrand_destroy_discrete_distribution(discrete_distribution));
    }

    delete[] host_output;
    HIP_CHECK(hipFree(device_output));
    HIP_CHECK(hipFree(device_states));
}

/* #################################################

                TEST HOST SIDE

   ###############################################*/

#include "rng/distribution/discrete.hpp"

template<typename T, class DiscreteFunc>
void run_internal_host_test(const DiscreteFunc& df)
{
    constexpr size_t test_size = 100000;

    std::vector<std::vector<double>> all_distributions = {
        {10, 10, 10, 10},
        {1, 2, 3, 4, 5, 6, 5, 4, 3, 2, 1},
        {1234, 1677, 1519, 1032, 561, 254, 98, 33, 10, 2},
        {1, 2, 8, 4, 3, 2, 1}
    };

    std::random_device rd;
    std::mt19937       gen(rd());

    std::vector<T>            input(test_size);
    std::vector<unsigned int> histogram(test_size, 0);

    // Check for different types of data input and generate the input data
    if constexpr(std::is_same_v<T, double>)
    {
        std::uniform_real_distribution<double> dis(0, 1);
        for(size_t i = 0; i < test_size; i++)
            input[i] = dis(gen);
    }
    else if constexpr(std::is_same_v<T, unsigned long> || std::is_same_v<T, unsigned int>)
    {
        std::uniform_int_distribution<T> dis(0, std::numeric_limits<unsigned int>::max());
        for(size_t i = 0; i < test_size; i++)
            input[i] = dis(gen);
    }
    else
    {
        std::uniform_int_distribution<T> dis(0, std::numeric_limits<T>::max());
        for(size_t i = 0; i < test_size; i++)
            input[i] = dis(gen);
    }

    for(std::vector<double> distribution : all_distributions)
    {
        // Getting expected Results
        double              sum = std::accumulate(distribution.begin(), distribution.end(), 0);
        std::vector<double> expected_prob(distribution.size());
        for(size_t i = 0; i < distribution.size(); i++)
            expected_prob[i] = distribution[i] / sum;

        // Creating the discrete distribution
        rocrand_discrete_distribution_st discrete_dis;

        using namespace rocrand_impl::host;

        rocrand_status rocrand_err
            = discrete_distribution_factory<discrete_method::DISCRETE_METHOD_UNIVERSAL,
                                            true>::create(distribution,
                                                          distribution.size(),
                                                          0,
                                                          discrete_dis);

        ROCRAND_CHECK(rocrand_err);
        std::vector<double> histogram(distribution.size());
        for(size_t i = 0; i < test_size; i++)
        {
            histogram[df(input[i], discrete_dis)]++;
        }

        std::vector<double> actual_prob(distribution.size());
        for(size_t i = 0; i < actual_prob.size(); i++)
            actual_prob[i] = histogram[i] / static_cast<double>(test_size);

        ASSERT_TRUE(ks_test_2(expected_prob, actual_prob));

        rocrand_err = discrete_distribution_factory<discrete_method::DISCRETE_METHOD_UNIVERSAL,
                                                    true>::deallocate(discrete_dis);
        ROCRAND_CHECK(rocrand_err);
    }
}

template<typename InType, bool UseDiscreteAlias>
struct InternalHostParams
{
    using T                   = InType;
    static constexpr bool uda = UseDiscreteAlias;
};

using InternalDiscreteHostParams
    = ::testing::Types<InternalHostParams<double, true>,
                       InternalHostParams<unsigned int, true>,
                       InternalHostParams<unsigned long, true>,
                       InternalHostParams<unsigned long long int, true>,
                       InternalHostParams<double, false>,
                       InternalHostParams<unsigned int, false>,
                       InternalHostParams<unsigned long, false>,
                       InternalHostParams<unsigned long long int, false>>;

template<class InternalHostParams>
class InternalDiscreteHostTest : public ::testing::Test
{
public:
    using input_type                         = typename InternalHostParams::T;
    static constexpr bool use_discrete_alias = InternalHostParams::uda;
};

TYPED_TEST_SUITE(InternalDiscreteHostTest, InternalDiscreteHostParams);

TYPED_TEST(InternalDiscreteHostTest, discrete_host_internal)
{
    using input_type                         = typename TestFixture::input_type;
    static constexpr bool use_discrete_alias = TestFixture::use_discrete_alias;

    if constexpr(use_discrete_alias)
    {
        run_internal_host_test<input_type>(
            [=](const input_type& x, rocrand_discrete_distribution_st& dis)
            { return rocrand_device::detail::discrete_alias(x, dis); });
    }
    else
    {
        run_internal_host_test<input_type>(
            [=](const input_type& x, rocrand_discrete_distribution_st& dis)
            { return rocrand_device::detail::discrete_cdf(x, dis); });
    }
}

template<class RocrandPRNGType>
inline void GetRocrandState(RocrandPRNGType* host_state)
{

    if constexpr(std::is_same_v<RocrandPRNGType, rocrand_state_sobol32>)
    {
        const unsigned int* directions;
        ROCRAND_CHECK(
            rocrand_get_direction_vectors32(&directions, ROCRAND_DIRECTION_VECTORS_32_JOEKUO6));
        rocrand_init(directions, 123456, host_state);
    }
    // scrambled sobol32 case
    else if constexpr(std::is_same_v<RocrandPRNGType, rocrand_state_scrambled_sobol32>)
    {
        const unsigned int* directions;
        ROCRAND_CHECK(
            rocrand_get_direction_vectors32(&directions, ROCRAND_DIRECTION_VECTORS_32_JOEKUO6));
        rocrand_init(directions, 123456, 654321, host_state);
    }
    // sobol64 case
    else if constexpr(std::is_same_v<RocrandPRNGType, rocrand_state_sobol64>)
    {
        const unsigned long long* directions;
        ROCRAND_CHECK(
            rocrand_get_direction_vectors64(&directions, ROCRAND_DIRECTION_VECTORS_64_JOEKUO6));
        rocrand_init(directions, 123456, host_state);
    }
    // scrambled sobol64 case
    else if constexpr(std::is_same_v<RocrandPRNGType, rocrand_state_scrambled_sobol64>)
    {
        const unsigned long long* directions;
        ROCRAND_CHECK(
            rocrand_get_direction_vectors64(&directions, ROCRAND_DIRECTION_VECTORS_64_JOEKUO6));
        rocrand_init(directions, 123456, 654321, host_state);
    }
    // lfsr113 case
    else if constexpr(std::is_same_v<RocrandPRNGType, rocrand_state_lfsr113>)
    {
        rocrand_init({0xabcd, 0xdabc, 0xcdab, 0xbcda}, 0, 0, host_state);
    }
    else
    {
        rocrand_init(123456, 654321, 0, host_state);
    }
}

template<typename RocrandPRNGType, class DiscreteFunc>
void run_host_test(const DiscreteFunc& df)
{
    constexpr size_t test_size = 100000;

    std::vector<std::vector<double>> all_distributions = {
        {10, 10, 10, 10},
        {1, 2, 3, 4, 5, 6, 5, 4, 3, 2, 1},
        {1234, 1677, 1519, 1032, 561, 254, 98, 33, 10, 2},
        {1, 2, 8, 4, 3, 2, 1}
    };

    RocrandPRNGType generator;
    GetRocrandState(&generator);

    for(std::vector<double> distribution : all_distributions)
    {
        // Getting expected Results
        double              sum = std::accumulate(distribution.begin(), distribution.end(), 0);
        std::vector<double> expected_prob(distribution.size());
        for(size_t i = 0; i < distribution.size(); i++)
            expected_prob[i] = distribution[i] / sum;

        // Creating the discrete distribution
        rocrand_discrete_distribution_st discrete_dis;

        using namespace rocrand_impl::host;

        rocrand_status rocrand_err
            = discrete_distribution_factory<discrete_method::DISCRETE_METHOD_UNIVERSAL,
                                            true>::create(distribution,
                                                          distribution.size(),
                                                          0,
                                                          discrete_dis);

        ROCRAND_CHECK(rocrand_err);
        std::vector<double> histogram(distribution.size());
        for(size_t i = 0; i < test_size; i++)
        {
            histogram[df(&generator, &discrete_dis)]++;
        }

        std::vector<double> actual_prob(distribution.size());
        for(size_t i = 0; i < actual_prob.size(); i++)
            actual_prob[i] = histogram[i] / static_cast<double>(test_size);

        ASSERT_TRUE(ks_test_2(expected_prob, actual_prob));

        rocrand_err = discrete_distribution_factory<discrete_method::DISCRETE_METHOD_UNIVERSAL,
                                                    true>::deallocate(discrete_dis);
        ROCRAND_CHECK(rocrand_err);
    }
}

using DiscreteHostParams = ::testing::Types<rocrand_state_philox4x32_10,
                                            rocrand_state_mrg31k3p,
                                            rocrand_state_mrg32k3a,
                                            rocrand_state_xorwow,
                                            rocrand_state_sobol32,
                                            rocrand_state_scrambled_sobol32,
                                            rocrand_state_sobol64,
                                            rocrand_state_scrambled_sobol64,
                                            rocrand_state_lfsr113,
                                            rocrand_state_threefry2x32_20,
                                            rocrand_state_threefry2x64_20,
                                            rocrand_state_threefry4x32_20,
                                            rocrand_state_threefry4x64_20>;

template<typename T>
class DiscreteHostTest : public ::testing::Test
{
public:
    using rocrand_prng_type = T;
};

TYPED_TEST_SUITE(DiscreteHostTest, DiscreteHostParams);

TYPED_TEST(DiscreteHostTest, discrete_host)
{
    using rocrand_prng_type = typename TestFixture::rocrand_prng_type;

    run_host_test<rocrand_prng_type>(
        [=](rocrand_prng_type* x, rocrand_discrete_distribution_st* dis)
        { return rocrand_discrete(x, dis); });
}