- SUBROUTINE DLARFX(
- SIDE, M, N, V, TAU, C, LDC, WORK )
- IMPLICIT NONE
- CHARACTER SIDE
- INTEGER LDC, M, N
- DOUBLE PRECISION TAU
- DOUBLE PRECISION C( LDC, * ), V( * ), WORK( * )
PURPOSEDLARFX 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 form
H = I - tau * v * v'
where tau is a real scalar and v is a real vector.
If tau = 0, then H is taken to be the unit matrix
This version uses inline code if H has order < 11.
- SIDE (input) CHARACTER*1
= 'L': form H * C
= 'R': 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.
- V (input) DOUBLE PRECISION array, dimension (M) if SIDE = 'L'
- or (N) if SIDE = 'R' The vector v in the representation of H.
- TAU (input) DOUBLE PRECISION
- The value tau in the representation of H.
- C (input/output) DOUBLE PRECISION array, dimension (LDC,N)
- On entry, the m by n matrix C. On exit, C is overwritten by the matrix H * C if SIDE = 'L', or C * H if SIDE = 'R'.
- LDC (input) INTEGER
- The leading dimension of the array C. LDA >= (1,M).
- WORK (workspace) DOUBLE PRECISION array, dimension
(N) if SIDE = 'L'
or (M) if SIDE = 'R'
WORK is not referenced if H has order < 11.