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#include <cblas.h>
#include <stdio.h>
double m[] = {
3, 1, 3,
1, 5, 9,
2, 6, 5
};
double x[] = {
-1, 3, -3
};
#ifdef __cplusplus
extern "C" {
#endif
void dgesv_(int *n, int *nrhs, double *a, int *lda,
int *ipivot, double *b, int *ldb, int *info);
#ifdef __cplusplus
}
#endif
int main(void) {
int i;
// blas:
double A[6] = {1.0, 2.0, 1.0, -3.0, 4.0, -1.0};
double B[6] = {1.0, 2.0, 1.0, -3.0, 4.0, -1.0};
double C[9] = {.5, .5, .5, .5, .5, .5, .5, .5, .5};
cblas_dgemm(CblasColMajor, CblasNoTrans, CblasTrans,
3, 3, 2, 1, A, 3, B, 3, 2, C, 3);
for (i = 0; i < 9; i++)
printf("%f\n", C[i]);
// lapack:
int ipiv[3];
int j;
int info;
int n = 1;
int nrhs = 1;
int lda = 3;
int ldb = 3;
dgesv_(&n,&nrhs, &m[0], &lda, ipiv, &x[0], &ldb, &info);
for (i=0; i<3; ++i)
printf("%5.1f\n", x[i]);
return 0;
}
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