CBLAS / LAPACKE test program

Makefile

LDLIBS += -lcblas -llapacke

.PHONY: clean

test: test.o

clean:
	$(RM) test.o test

test.c

#include <stdio.h>
#include <cblas.h>
#include <lapacke.h>

int main (int argc, char *argv[]) {
    const double A[3*3] = { 1, 2, 3,
                            4, 5, 6,
                            7, 8, 9};
    double B[3*3] = { 0.5, 0.0, -0.5,
                            0.0, 1.0,  0.0,
                            -.5, 0.0,  0.5};
    double C[3*3] = { 0, 0, 0,
                      0, 0, 0,
                      0, 0, 0};
    cblas_dgemm(CblasRowMajor, CblasNoTrans, CblasNoTrans, 3, 3, 3, 1.0,
                A, 3, B, 3, 0.0, C, 3);
    int i, j;
    for (i = 0; i < 3; i++) {
        for (j = 0; j < 3; j++)
            printf("%3f\t", C[3*i+j]);
        printf("\n");
    }

    double D[3];
    double E[2];
    double TAU[2];
    LAPACKE_dsytrd(LAPACK_ROW_MAJOR, 'U', 3, B, 3, D, E, TAU);
    printf("Tridiagonal:\n%3f\t%3f\t%3f\n%3f\t%3f\t%3f\n%3f\t%3f\t%3f\n",
           D[0], E[0], 0.,
           E[0], D[1], E[1],
             0., E[1], D[2]);
    LAPACKE_dsterf(3, D, E);
    printf("Eigenvalues: %3f, %3f, %3f\n", D[0], D[1], D[2]);
    return 0;
}