slarz (l) - Linux Manuals
slarz: applies a real elementary reflector H to a real M-by-N matrix C, from either the left or the right
NAME
SLARZ - applies a real elementary reflector H to a real M-by-N matrix C, from either the left or the rightSYNOPSIS
- SUBROUTINE SLARZ(
- SIDE, M, N, L, V, INCV, TAU, C, LDC, WORK )
- CHARACTER SIDE
- INTEGER INCV, L, LDC, M, N
- REAL TAU
- REAL C( LDC, * ), V( * ), WORK( * )
PURPOSE
SLARZ applies a real elementary reflector H to a real M-by-N matrix C, from either the left or the right. H is represented in the formH
where tau is a real scalar and v is a real vector.
If tau = 0, then H is taken to be the unit matrix.
H is a product of k elementary reflectors as returned by STZRZF.
ARGUMENTS
- SIDE (input) CHARACTER*1
-
= aqLaq: form H * C
= aqRaq: form C * H - M (input) INTEGER
- The number of rows of the matrix C.
- N (input) INTEGER
- The number of columns of the matrix C.
- L (input) INTEGER
- The number of entries of the vector V containing the meaningful part of the Householder vectors. If SIDE = aqLaq, M >= L >= 0, if SIDE = aqRaq, N >= L >= 0.
- V (input) REAL array, dimension (1+(L-1)*abs(INCV))
- The vector v in the representation of H as returned by STZRZF. V is not used if TAU = 0.
- INCV (input) INTEGER
- The increment between elements of v. INCV <> 0.
- TAU (input) REAL
- The value tau in the representation of H.
- C (input/output) REAL array, dimension (LDC,N)
- On entry, the M-by-N matrix C. On exit, C is overwritten by the matrix H * C if SIDE = aqLaq, or C * H if SIDE = aqRaq.
- LDC (input) INTEGER
- The leading dimension of the array C. LDC >= max(1,M).
- WORK (workspace) REAL array, dimension
- (N) if SIDE = aqLaq or (M) if SIDE = aqRaq
FURTHER DETAILS
Based on contributions by