/* ************************************************************************
 * Copyright (C) 2016-2025 Advanced Micro Devices, Inc. All rights reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 * ************************************************************************ */

#include <hipblas/hipblas.h>
#include <iostream>
#include <limits>
#include <stdio.h>
#include <stdlib.h>
#include <vector>

#ifndef CHECK_HIP_ERROR
#define CHECK_HIP_ERROR(error)                    \
    if(error != hipSuccess)                       \
    {                                             \
        fprintf(stderr,                           \
                "Hip error: '%s'(%d) at %s:%d\n", \
                hipGetErrorString(error),         \
                error,                            \
                __FILE__,                         \
                __LINE__);                        \
        exit(EXIT_FAILURE);                       \
    }
#endif

#ifndef CHECK_HIPBLAS_ERROR
#define CHECK_HIPBLAS_ERROR(error)                              \
    if(error != HIPBLAS_STATUS_SUCCESS)                         \
    {                                                           \
        fprintf(stderr, "hipBLAS error: ");                     \
        if(error == HIPBLAS_STATUS_NOT_INITIALIZED)             \
            fprintf(stderr, "HIPBLAS_STATUS_NOT_INITIALIZED");  \
        if(error == HIPBLAS_STATUS_ALLOC_FAILED)                \
            fprintf(stderr, "HIPBLAS_STATUS_ALLOC_FAILED");     \
        if(error == HIPBLAS_STATUS_INVALID_VALUE)               \
            fprintf(stderr, "HIPBLAS_STATUS_INVALID_VALUE");    \
        if(error == HIPBLAS_STATUS_MAPPING_ERROR)               \
            fprintf(stderr, "HIPBLAS_STATUS_MAPPING_ERROR");    \
        if(error == HIPBLAS_STATUS_EXECUTION_FAILED)            \
            fprintf(stderr, "HIPBLAS_STATUS_EXECUTION_FAILED"); \
        if(error == HIPBLAS_STATUS_INTERNAL_ERROR)              \
            fprintf(stderr, "HIPBLAS_STATUS_INTERNAL_ERROR");   \
        if(error == HIPBLAS_STATUS_NOT_SUPPORTED)               \
            fprintf(stderr, "HIPBLAS_STATUS_NOT_SUPPORTED");    \
        if(error == HIPBLAS_STATUS_INVALID_ENUM)                \
            fprintf(stderr, "HIPBLAS_STATUS_INVALID_ENUM");     \
        if(error == HIPBLAS_STATUS_UNKNOWN)                     \
            fprintf(stderr, "HIPBLAS_STATUS_UNKNOWN");          \
        fprintf(stderr, "\n");                                  \
        exit(EXIT_FAILURE);                                     \
    }
#endif

#define DIM1 1023
#define DIM2 1024
#define DIM3 1025

void mat_mat_mult_half(__half  alpha,
                       __half  beta,
                       int     M,
                       int     N,
                       int     K,
                       __half* A,
                       int     As1,
                       int     As2,
                       __half* B,
                       int     Bs1,
                       int     Bs2,
                       __half* C,
                       int     Cs1,
                       int     Cs2)
{
    float beta_float  = __half2float(beta);
    float alpha_float = __half2float(alpha);
    for(int i1 = 0; i1 < M; i1++)
    {
        for(int i2 = 0; i2 < N; i2++)
        {
            float t     = 0.0;
            float C_val = __half2float(C[i1 * Cs1 + i2 * Cs2]);
            for(int i3 = 0; i3 < K; i3++)
            {
                float A_val = __half2float(A[i1 * As1 + i3 * As2]);
                float B_val = __half2float(B[i3 * Bs1 + i2 * Bs2]);
                t += A_val * B_val;
            }
            C[i1 * Cs1 + i2 * Cs2] = __float2half(beta_float * C_val + alpha_float * t);
        }
    }
}

int main()
{
    hipblasOperation_t transa = HIPBLAS_OP_N, transb = HIPBLAS_OP_T;
    const __half       alpha = 1.1, beta = 0.9;

    int m = DIM1, n = DIM2, k = DIM3;
    int lda, ldb, ldc, size_a, size_b, size_c;
    int a_stride_1, a_stride_2, b_stride_1, b_stride_2;
    std::cout << "hgemm __half example" << std::endl;
    if(transa == HIPBLAS_OP_N)
    {
        lda        = m;
        size_a     = k * lda;
        a_stride_1 = 1;
        a_stride_2 = lda;
        std::cout << "N";
    }
    else
    {
        lda        = k;
        size_a     = m * lda;
        a_stride_1 = lda;
        a_stride_2 = 1;
        std::cout << "T";
    }
    if(transb == HIPBLAS_OP_N)
    {
        ldb        = k;
        size_b     = n * ldb;
        b_stride_1 = 1;
        b_stride_2 = ldb;
        std::cout << "N: ";
    }
    else
    {
        ldb        = n;
        size_b     = k * ldb;
        b_stride_1 = ldb;
        b_stride_2 = 1;
        std::cout << "T: ";
    }
    ldc    = m;
    size_c = n * ldc;

    // Naming: da is in GPU (device) memory. ha is in CPU (host) memory
    std::vector<__half> ha(size_a);
    std::vector<__half> hb(size_b);
    std::vector<__half> hc(size_c);
    std::vector<__half> hc_gold(size_c);

    // initial data on host
    srand(1);
    for(int i = 0; i < size_a; ++i)
    {
        // random number in [-2, 2]
        ha[i] = __float2half(rand() % 5 - 2.0f);
    }
    for(int i = 0; i < size_b; ++i)
    {
        hb[i] = __float2half(rand() % 5 - 2.0f);
    }
    for(int i = 0; i < size_c; ++i)
    {
        hc[i] = __float2half(rand() % 5 - 2.0f);
    }
    hc_gold = hc;

    // allocate memory on device
    __half *da, *db, *dc;
    CHECK_HIP_ERROR(hipMalloc(&da, size_a * sizeof(__half)));
    CHECK_HIP_ERROR(hipMalloc(&db, size_b * sizeof(__half)));
    CHECK_HIP_ERROR(hipMalloc(&dc, size_c * sizeof(__half)));

    // copy matrices from host to device
    CHECK_HIP_ERROR(hipMemcpy(da, ha.data(), sizeof(__half) * size_a, hipMemcpyHostToDevice));
    CHECK_HIP_ERROR(hipMemcpy(db, hb.data(), sizeof(__half) * size_b, hipMemcpyHostToDevice));
    CHECK_HIP_ERROR(hipMemcpy(dc, hc.data(), sizeof(__half) * size_c, hipMemcpyHostToDevice));

    hipblasHandle_t handle;
    CHECK_HIPBLAS_ERROR(hipblasCreate(&handle));

    CHECK_HIPBLAS_ERROR(
        hipblasHgemm(handle, transa, transb, m, n, k, &alpha, da, lda, db, ldb, &beta, dc, ldc));

    // copy output from device to CPU
    CHECK_HIP_ERROR(hipMemcpy(hc.data(), dc, sizeof(__half) * size_c, hipMemcpyDeviceToHost));

    std::cout << "m, n, k, lda, ldb, ldc = " << m << ", " << n << ", " << k << ", " << lda << ", "
              << ldb << ", " << ldc << std::endl;

    float max_relative_error = 0;

    // calculate golden or correct result
    mat_mat_mult_half(alpha,
                      beta,
                      m,
                      n,
                      k,
                      ha.data(),
                      a_stride_1,
                      a_stride_2,
                      hb.data(),
                      b_stride_1,
                      b_stride_2,
                      hc_gold.data(),
                      1,
                      ldc);

    for(int i = 0; i < size_c; i++)
    {
        float hc_gold_val = __half2float(hc_gold[i]);
        float hc_val      = __half2float(hc[i]);
        float relative_error
            = hc_gold_val == 0 ? (hc_gold_val - hc_val) : (hc_gold_val - hc_val) / hc_gold_val;
        relative_error = relative_error > 0 ? relative_error : -relative_error;
        max_relative_error
            = relative_error < max_relative_error ? max_relative_error : relative_error;
    }

    float half_eps = 0.000488; // approx 2^-11, rounding machine epsilon for ieee754 half precision

    // tolerance is arbitrary right now
    float tolerance = 20;
    if(max_relative_error != max_relative_error || max_relative_error > half_eps * tolerance)
    {
        std::cout << "FAIL: max_relative_error = " << max_relative_error << std::endl;
    }
    else
    {
        std::cout << "PASS: max_relative_error = " << max_relative_error << std::endl;
    }

    CHECK_HIP_ERROR(hipFree(da));
    CHECK_HIP_ERROR(hipFree(db));
    CHECK_HIP_ERROR(hipFree(dc));
    CHECK_HIPBLAS_ERROR(hipblasDestroy(handle));
    return EXIT_SUCCESS;
}