TheRock/rocm-libraries/projects/rocsparse/clients/samples/example_bsrsv.cpp

/*! \file */
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 * Copyright (C) 2020-2025 Advanced Micro Devices, Inc. All rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
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 * 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.
 *
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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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#include "rocsparse/rocsparse.h"
#include <hip/hip_runtime_api.h>
#include <iostream>

#define HIP_CHECK(stat)                                                        \
    {                                                                          \
        if(stat != hipSuccess)                                                 \
        {                                                                      \
            std::cerr << "Error: hip error in line " << __LINE__ << std::endl; \
            return -1;                                                         \
        }                                                                      \
    }

#define ROCSPARSE_CHECK(stat)                                                        \
    {                                                                                \
        if(stat != rocsparse_status_success)                                         \
        {                                                                            \
            std::cerr << "Error: rocsparse error in line " << __LINE__ << std::endl; \
            return -1;                                                               \
        }                                                                            \
    }

int main(int argc, char* argv[])
{
    // Query device
    int ndev;
    HIP_CHECK(hipGetDeviceCount(&ndev));

    if(ndev < 1)
    {
        std::cerr << "No HIP device found" << std::endl;
        return -1;
    }

    // Query device properties
    hipDeviceProp_t prop;
    HIP_CHECK(hipGetDeviceProperties(&prop, 0));

    std::cout << "Device: " << prop.name << std::endl;

    // rocSPARSE handle
    rocsparse_handle handle;
    ROCSPARSE_CHECK(rocsparse_create_handle(&handle));

    // Print rocSPARSE version and revision
    int  ver;
    char rev[64];

    ROCSPARSE_CHECK(rocsparse_get_version(handle, &ver));
    ROCSPARSE_CHECK(rocsparse_get_git_rev(handle, rev));

    std::cout << "rocSPARSE version: " << ver / 100000 << "." << ver / 100 % 1000 << "."
              << ver % 100 << "-" << rev << std::endl;

    // Input data

    // A = ( 1.0  0.0  0.0  0.0 )
    //     ( 2.0  3.0  0.0  0.0 )
    //     ( 4.0  5.0  6.0  0.0 )
    //     ( 7.0  0.0  8.0  9.0 )
    //
    // with bsr_dim = 2
    //
    //      -------------------
    //   = | 1.0 0.0 | 0.0 0.0 |
    //     | 2.0 3.0 | 0.0 0.0 |
    //      -------------------
    //     | 4.0 5.0 | 6.0 0.0 |
    //     | 7.0 0.0 | 8.0 9.0 |
    //      -------------------

    // Number of rows and columns
    rocsparse_int m = 4;

    // Number of block rows and block columns
    rocsparse_int mb = 2;
    rocsparse_int nb = 2;

    // BSR block dimension
    rocsparse_int bsr_dim = 2;

    // Number of non-zero blocks
    rocsparse_int nnzb = 3;

    // BSR row pointers
    rocsparse_int hbsr_row_ptr[3] = {0, 1, 3};

    // BSR column indices
    rocsparse_int hbsr_col_ind[3] = {0, 0, 1};

    // BSR values
    double hbsr_val[12] = {1.0, 2.0, 0.0, 3.0, 4.0, 7.0, 5.0, 0.0, 6.0, 8.0, 0.0, 9.0};

    // Storage scheme of the BSR blocks
    rocsparse_direction dir = rocsparse_direction_column;

    // Transposition of the matrix
    rocsparse_operation trans = rocsparse_operation_none;

    // Analysis policy
    rocsparse_analysis_policy analysis_policy = rocsparse_analysis_policy_reuse;

    // Solve policy
    rocsparse_solve_policy solve_policy = rocsparse_solve_policy_auto;

    // Scalar alpha and beta
    double alpha = 3.7;

    // x
    double hx[4] = {1.0, 2.0, 3.0, 4.0};
    double hy[4];

    // Offload data to device
    rocsparse_int* dbsr_row_ptr;
    rocsparse_int* dbsr_col_ind;
    double*        dbsr_val;
    double*        dx;
    double*        dy;

    HIP_CHECK(hipMalloc((void**)&dbsr_row_ptr, sizeof(rocsparse_int) * (mb + 1)));
    HIP_CHECK(hipMalloc((void**)&dbsr_col_ind, sizeof(rocsparse_int) * nnzb));
    HIP_CHECK(hipMalloc((void**)&dbsr_val, sizeof(double) * nnzb * bsr_dim * bsr_dim));
    HIP_CHECK(hipMalloc((void**)&dx, sizeof(double) * nb * bsr_dim));
    HIP_CHECK(hipMalloc((void**)&dy, sizeof(double) * mb * bsr_dim));

    HIP_CHECK(hipMemcpy(
        dbsr_row_ptr, hbsr_row_ptr, sizeof(rocsparse_int) * (mb + 1), hipMemcpyHostToDevice));
    HIP_CHECK(
        hipMemcpy(dbsr_col_ind, hbsr_col_ind, sizeof(rocsparse_int) * nnzb, hipMemcpyHostToDevice));
    HIP_CHECK(hipMemcpy(
        dbsr_val, hbsr_val, sizeof(double) * nnzb * bsr_dim * bsr_dim, hipMemcpyHostToDevice));
    HIP_CHECK(hipMemcpy(dx, hx, sizeof(double) * nb * bsr_dim, hipMemcpyHostToDevice));
    HIP_CHECK(hipMemcpy(dy, hy, sizeof(double) * mb * bsr_dim, hipMemcpyHostToDevice));

    // Matrix descriptor
    rocsparse_mat_descr descr;
    ROCSPARSE_CHECK(rocsparse_create_mat_descr(&descr));

    // Matrix fill mode
    ROCSPARSE_CHECK(rocsparse_set_mat_fill_mode(descr, rocsparse_fill_mode_lower));

    // Matrix diagonal type
    ROCSPARSE_CHECK(rocsparse_set_mat_diag_type(descr, rocsparse_diag_type_unit));

    // Matrix info structure
    rocsparse_mat_info info;
    ROCSPARSE_CHECK(rocsparse_create_mat_info(&info));

    // Obtain required buffer size
    size_t buffer_size;
    ROCSPARSE_CHECK(rocsparse_dbsrsv_buffer_size(handle,
                                                 dir,
                                                 trans,
                                                 mb,
                                                 nnzb,
                                                 descr,
                                                 dbsr_val,
                                                 dbsr_row_ptr,
                                                 dbsr_col_ind,
                                                 bsr_dim,
                                                 info,
                                                 &buffer_size));

    // Allocate temporary buffer
    std::cout << "Allocating " << (buffer_size >> 10) << "kB temporary storage buffer" << std::endl;

    void* temp_buffer;
    HIP_CHECK(hipMalloc(&temp_buffer, buffer_size));

    // Perform analysis step
    ROCSPARSE_CHECK(rocsparse_dbsrsv_analysis(handle,
                                              dir,
                                              trans,
                                              mb,
                                              nnzb,
                                              descr,
                                              dbsr_val,
                                              dbsr_row_ptr,
                                              dbsr_col_ind,
                                              bsr_dim,
                                              info,
                                              analysis_policy,
                                              solve_policy,
                                              temp_buffer));

    // Call dbsrsv to perform lower triangular solve Ly = x
    ROCSPARSE_CHECK(rocsparse_dbsrsv_solve(handle,
                                           dir,
                                           trans,
                                           mb,
                                           nnzb,
                                           &alpha,
                                           descr,
                                           dbsr_val,
                                           dbsr_row_ptr,
                                           dbsr_col_ind,
                                           bsr_dim,
                                           info,
                                           dx,
                                           dy,
                                           solve_policy,
                                           temp_buffer));

    // Check for zero pivots
    rocsparse_int    pivot;
    rocsparse_status status = rocsparse_bsrsv_zero_pivot(handle, info, &pivot);

    if(status == rocsparse_status_zero_pivot)
    {
        std::cout << "Found zero pivot in matrix row " << pivot << std::endl;
    }

    // Print result
    HIP_CHECK(hipMemcpy(hy, dy, sizeof(double) * m, hipMemcpyDeviceToHost));

    std::cout << "y:";

    for(int i = 0; i < m; ++i)
    {
        std::cout << " " << hy[i];
    }

    std::cout << std::endl;

    // Clear rocSPARSE
    ROCSPARSE_CHECK(rocsparse_destroy_mat_info(info));
    ROCSPARSE_CHECK(rocsparse_destroy_mat_descr(descr));
    ROCSPARSE_CHECK(rocsparse_destroy_handle(handle));

    // Clear device memory
    HIP_CHECK(hipFree(dbsr_row_ptr));
    HIP_CHECK(hipFree(dbsr_col_ind));
    HIP_CHECK(hipFree(dbsr_val));
    HIP_CHECK(hipFree(dx));
    HIP_CHECK(hipFree(dy));
    HIP_CHECK(hipFree(temp_buffer));

    return 0;
}