(S|D|C|Z)LARF¶

Single, double, single complex, and double complex LARF.

Description¶

Applies an elementary reflector to a rectangular matrix from the left or right.

If SIDE is ‘L’,

$C \assign H * C$

If SIDE is ‘R’,

$C \assign C * H$

The reflector is:

$H = I - \tau \mult v \mult \trans{v}$

LAPACK Interface¶

void slarf(const char *SIDE, const qml_long *M, const qml_long *N, const float *V,
    const qml_long *INCV, const float *TAU, float *C, const qml_long *LDC,
    float *WORK);

void dlarf(const char *SIDE, const qml_long *M, const qml_long *N, const double *V,
    const qml_long *INCV, const double *TAU, double *C, const qml_long *LDC,
    double *WORK);

void clarf(const char *SIDE, const qml_long *M, const qml_long *N,
    const qml_single_complex *V, const qml_long *INCV, const qml_single_complex *TAU,
    qml_single_complex *C, const qml_long *LDC, qml_single_complex *WORK);

void zlarf(const char *SIDE, const qml_long *M, const qml_long *N,
    const qml_double_complex *V, const qml_long *INCV, const qml_double_complex *TAU,
    qml_double_complex *C, const qml_long *LDC, qml_double_complex *WORK);

Arguments¶

SIDE	Which side to mulplify reflector from, ‘L’ or ‘R’
M	Number of rows of C
N	Number of columns of C
V	Vector representing reflector
INCV	Stride between elements in V
TAU	Scale factor for elementary reflector
C	Matrix of size M x N
LDC	Leading dimension of C
WORK	Work space of size at least N if SIDE is ‘L’, or M if SIDE is ‘R’