subroutine dlarz (SIDE, M, N, L, V, INCV, TAU, C, LDC, WORK)
DLARZ applies an elementary reflector (as returned by stzrzf) to a general matrix.
DLARZ applies an elementary reflector (as returned by stzrzf) to a general matrix.
Purpose:
DLARZ 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**T 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 DTZRZF.
Parameters:
SIDE is CHARACTER*1 = 'L': form H * C = 'R': form C * H
M
M is INTEGER The number of rows of the matrix C.
N
N is INTEGER The number of columns of the matrix C.
L
L is INTEGER The number of entries of the vector V containing the meaningful part of the Householder vectors. If SIDE = 'L', M >= L >= 0, if SIDE = 'R', N >= L >= 0.
V
V is DOUBLE PRECISION array, dimension (1+(L-1)*abs(INCV)) The vector v in the representation of H as returned by DTZRZF. V is not used if TAU = 0.
INCV
INCV is INTEGER The increment between elements of v. INCV <> 0.
TAU
TAU is DOUBLE PRECISION The value tau in the representation of H.
C
C is 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
LDC is INTEGER The leading dimension of the array C. LDC >= max(1,M).
WORK
WORK is DOUBLE PRECISION array, dimension (N) if SIDE = 'L' or (M) if SIDE = 'R'
Author:
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date:
Contributors:
Further Details:
Definition at line 147 of file dlarz.f.
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