(S|D|C|Z)GESV¶

Single, double, single complex, and double complex GESV.

Description¶

Uses LU decomposition with pivoting to solve the equation:

$A \mult X = B$

The LU decomposition with partial pivoting is used to factor A as:

$A = P \mult L \mult U$

where P is a permutation matrix, L is unit lower triangular and U is upper triangular. On exit, L and U overwrite A (the unit diagonal is not stored), the locations of pivots are stored in IPIV, and the solution matrix X overwrites B.

LAPACK Interface¶

void sgesv(const qml_long *N, const qml_long *NRHS, float *A, const qml_long *LDA,
    qml_long *IPIV, float *B, const qml_long *LDB, qml_long *INFO);

void dgesv(const qml_long *N, const qml_long *NRHS, double *A, const qml_long *LDA,
    qml_long *IPIV, double *B, const qml_long *LDB, qml_long *INFO);

void cgesv(const qml_long *N, const qml_long *NRHS, qml_single_complex *A,
    const qml_long *LDA, qml_long *IPIV, qml_single_complex *B,
    const qml_long *LDB, qml_long *INFO);

void zgesv(const qml_long *N, const qml_long *NRHS, qml_double_complex *A,
    const qml_long *LDA, qml_long *IPIV, qml_double_complex *B,
    const qml_long *LDB, qml_long *INFO);

Arguments¶

N	Number of linear equations, order of A
NRHS	Number of right hand sides, number of columns of B
A	Matrix of size N x N
LDA	Leading dimension of A
IPIV	Pivot indices indicating rows to interchange
B	Matrix of size N x NRHS, overwritten with solutions
LDB	Leading dimension of B
INFO	0 on success, <0 for illegal arguments, >0 for singular decomposition