/// LAPACK
bool sv(RealVector &b, RealSquare &A) {
bool flag = true;
lapack_int n, nrhs, lda, ldb, info;
lapack_int *ipiv;
n = A.size, nrhs = 1, lda = n, ldb = nrhs;
ipiv = new lapack_int[n];
if (NULL == &A || NULL == &b) {
flag = false;
goto end;
}
if (A.size != b.size) {
flag = false;
goto end;
}
info = LAPACKE_sgesv(LAPACK_ROW_MAJOR, n, nrhs, A.M, lda, ipiv, b.M, ldb);
if (info > 0) {
printf("The diagonal element of the triangular factor of A,\n");
printf("U(%i,%i) is zero, so that A is singular;\n", info, info);
printf("the solution could not be computed.\n");
flag = false;
goto end;
}
end:
delete []ipiv; ipiv = NULL;
return flag;
}
int main(void)
{
int info, ipiv2[2];
float err = 1e-6;
float x2[2], b2[2], c2[2];
float a2x2[2][2];
//#cblas
x2[0] = 1.0;
x2[1] = -2.0;
assert_eqd( cblas_snrm2(2, x2, 1), sqrt(5.0), err );
//#lapacke
//1 2 x = 5
//3 4 y 11
//x = 1
//y = 1
a2x2[0][0] = 1.0;
a2x2[1][0] = 2.0;
a2x2[0][1] = 3.0;
a2x2[1][1] = 4.0;
b2[0] = 5.;
b2[1] = 11.;
info = LAPACKE_sgesv(
LAPACK_COL_MAJOR, //COL or ROW
2, //n
1, //nrhs
&a2x2[0][0],
2, //lda
&ipiv2[0],
&b2[0],
2 //ldb
);
c2[0] = 1.0;
c2[1] = 2.0;
assert_eqi( info, 0 );
assert_eqd( b2[0], c2[0], err );
assert_eqd( b2[1], c2[1], err );
return EXIT_SUCCESS;
}
template <> inline
int gesvd(const char order, const int N, const int M, float *A, const int LDA, int *IPIV, float *B, const int LDB)
{
return LAPACKE_sgesv(order, N, M, A, LDA, IPIV, B, LDB);
}
int main() {
float x[3] = {1,1,1};
float y[3] = {2,2,2};
//float dotProd = cblas_sdot(3, x, 1, y, 1);
//printf("%f\n", dotProd);
lapack_int nrhs = 1; // Cols of B, always 1 in our case
lapack_int numEqs = 3; // Size of side of matrix, or number of linear equations
lapack_int lda = numEqs;
lapack_int ldb = lda;
float matA[] = {3.,7.,1., 4.,2.,1., 1.,1.,0.};
float vecB[] = {0.,0.,1.};
lapack_int ipiv[3] = {0,0,0};
// Apparently the function can only work using LAPACK_COL_MAJOR order;
// investigate
lapack_int info = LAPACKE_sgesv(LAPACK_COL_MAJOR, numEqs, nrhs, matA,
lda, ipiv, vecB, lda);
// Can use status code to identify failures in computation; only
// status code=0 is good
printf("status code:%d\n",info);
for (int i=0; i < ldb; ++i) {
printf("%f\n", vecB[i]);
}
// Test situation where solution is not possible
// Now test inner product
// 14 args
// Matrix to be multiplied should be in col maj order
float sqA[] = {3.,2.,4., 2.,2.,4.};
float arrB[] = {1.,1.};
float matC[] = {0.,0.};
int rowsA = 3, colsA = 2;
int m = rowsA, n = 1, k = colsA;
int aLd = rowsA, bLd = colsA, cLd = rowsA;
float alpha = 1., beta = 1.;
// First try A * b
cblas_sgemm(CblasColMajor, CblasNoTrans, CblasNoTrans, m, n, k, alpha, sqA, aLd,
arrB, bLd, beta, matC, cLd);
printf("A*b\n");
for (int i=0; i < rowsA; ++i) {
printf("%f\n", matC[i]);
}
// Then try b_T * A
float arrB_T[] = {1.,1.,1.};
m = 1, n = colsA, k = rowsA;
aLd = rowsA;
bLd = rowsA; // For Op(b), not b itself
cLd = 1;
matC[0] = 0.; matC[1] = 0.; matC[2] = 0.;
cblas_sgemm(CblasColMajor, CblasTrans, CblasNoTrans, m, n, k, alpha, arrB_T, aLd,
sqA, bLd, beta, matC, cLd);
printf("b_T*A\n");
for (int i=0; i < colsA; ++i) {
printf("%f\n", matC[i]);
}
return 0;
}
