mkl实现矩阵不同列扩大不同倍数

MKL可以使用矩阵乘法函数cblas_dgemm()来实现矩阵扩大不同列的功能。具体步骤如下：

1. 定义原始矩阵A和列扩大倍数矩阵B，并计算出扩大后的矩阵C的列数。

double A[3][4] = {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 11, 12}};
double B[4] = {1, 2, 3, 4};
int m = 3, n = 4, p = 0;
for (int i = 0; i < n; i++) {
    p += B[i];
}
double C[m][p];

2. 将A和B转换为按列存储的一维数组，以便使用cblas_dgemm()函数。

double *a = (double*)malloc(sizeof(double) * m * n);
double *b = (double*)malloc(sizeof(double) * n);
double *c = (double*)malloc(sizeof(double) * m * p);
for (int i = 0; i < m; i++) {
    for (int j = 0; j < n; j++) {
        a[i * n + j] = A[i][j];
    }
}
for (int i = 0; i < n; i++) {
    b[i] = B[i];
}

3. 调用cblas_dgemm()函数进行矩阵乘法，将结果保存在C矩阵中。

cblas_dgemm(CblasRowMajor, CblasNoTrans, CblasNoTrans, m, p, n, 1, a, n, b, 1, 0, c, p);

4. 将结果矩阵C转换回二维数组形式。

for (int i = 0; i < m; i++) {
    for (int j = 0; j < p; j++) {
        C[i][j] = c[i * p + j];
    }
}

完整代码如下：

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

int main()
{
    double A[3][4] = {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 11, 12}};
    double B[4] = {1, 2, 3, 4};
    int m = 3, n = 4, p = 0;
    for (int i = 0; i < n; i++) {
        p += B[i];
    }
    double C[m][p];

    double *a = (double*)malloc(sizeof(double) * m * n);
    double *b = (double*)malloc(sizeof(double) * n);
    double *c = (double*)malloc(sizeof(double) * m * p);
    for (int i = 0; i < m; i++) {
        for (int j = 0; j < n; j++) {
            a[i * n + j] = A[i][j];
        }
    }
    for (int i = 0; i < n; i++) {
        b[i] = B[i];
    }

    cblas_dgemm(CblasRowMajor, CblasNoTrans, CblasNoTrans, m, p, n, 1, a, n, b, 1, 0, c, p);

    for (int i = 0; i < m; i++) {
        for (int j = 0; j < p; j++) {
            C[i][j] = c[i * p + j];
        }
    }

    for (int i = 0; i < m; i++) {
        for (int j = 0; j < p; j++) {
            printf("%.2f ", C[i][j]);
        }
        printf("\n");
    }

    free(a);
    free(b);
    free(c);

    return 0;
}
``