mkl如何构建coo格式的稀疏矩阵

MKL可以使用以下步骤构建COO格式的稀疏矩阵：

1. 定义稀疏矩阵的维度和非零元素的数量。

2. 分配COO格式的稀疏矩阵内存空间。

3. 使用MKL提供的函数将非零元素逐个插入到稀疏矩阵中，同时记录每个元素的行和列坐标。

4. 使用MKL提供的函数将COO格式的稀疏矩阵转换为其他稀疏矩阵格式，如CSR或CSC。

以下是一个简单的示例代码，演示如何使用MKL构建COO格式的稀疏矩阵：

#include <stdio.h>
#include "mkl.h"

int main()
{
    // Define the dimensions and number of non-zero elements of the sparse matrix
    int n = 3; // matrix size
    int nnz = 4; // number of non-zero elements

    // Allocate memory for the COO sparse matrix
    double* values = (double*)mkl_malloc(nnz * sizeof(double), 64);
    MKL_INT* row_indices = (MKL_INT*)mkl_malloc(nnz * sizeof(MKL_INT), 64);
    MKL_INT* col_indices = (MKL_INT*)mkl_malloc(nnz * sizeof(MKL_INT), 64);

    // Insert non-zero elements into the COO sparse matrix
    values[0] = 1.0;
    row_indices[0] = 0;
    col_indices[0] = 0;

    values[1] = 2.0;
    row_indices[1] = 0;
    col_indices[1] = 2;

    values[2] = 3.0;
    row_indices[2] = 1;
    col_indices[2] = 1;

    values[3] = 4.0;
    row_indices[3] = 2;
    col_indices[3] = 2;

    // Convert the COO sparse matrix to CSR format
    MKL_INT job[6];
    job[0] = 0; // convert COO to CSR
    job[1] = nnz; // number of non-zero elements
    job[2] = n; // matrix size
    job[3] = -1; // output array size (use default)
    job[4] = -1; // output array size (use default)
    job[5] = 0; // zero-based indexing
    double* csr_values = (double*)mkl_malloc(nnz * sizeof(double), 64);
    MKL_INT* csr_row_indices = (MKL_INT*)mkl_malloc((n + 1) * sizeof(MKL_INT), 64);
    MKL_INT* csr_col_indices = (MKL_INT*)mkl_malloc(nnz * sizeof(MKL_INT), 64);
    mkl_dcsrcoo(job, &n, csr_values, csr_row_indices, csr_col_indices, &nnz, values, row_indices, col_indices);

    // Print the CSR sparse matrix
    printf("CSR sparse matrix:\n");
    for (int i = 0; i < n + 1; i++)
    {
        printf("csr_row_indices[%d] = %d\n", i, csr_row_indices[i]);
    }
    for (int i = 0; i < nnz; i++)
    {
        printf("csr_values[%d] = %f, csr_col_indices[%d] = %d\n", i, csr_values[i], i, csr_col_indices[i]);
    }

    // Free memory
    mkl_free(values);
    mkl_free(row_indices);
    mkl_free(col_indices);
    mkl_free(csr_values);
    mkl_free(csr_row_indices);
    mkl_free(csr_col_indices);

    return 0;
}
``