dlarzb.f - Man Page
SRC/dlarzb.f
Synopsis
Functions/Subroutines
subroutine dlarzb (side, trans, direct, storev, m, n, k, l, v, ldv, t, ldt, c, ldc, work, ldwork)
DLARZB applies a block reflector or its transpose to a general matrix.
Function/Subroutine Documentation
subroutine dlarzb (character side, character trans, character direct, character storev, integer m, integer n, integer k, integer l, double precision, dimension( ldv, * ) v, integer ldv, double precision, dimension( ldt, * ) t, integer ldt, double precision, dimension( ldc, * ) c, integer ldc, double precision, dimension( ldwork, * ) work, integer ldwork)
DLARZB applies a block reflector or its transpose to a general matrix.
Purpose:
DLARZB applies a real block reflector H or its transpose H**T to a real distributed M-by-N C from the left or the right. Currently, only STOREV = 'R' and DIRECT = 'B' are supported.
- Parameters
SIDE
SIDE is CHARACTER*1 = 'L': apply H or H**T from the Left = 'R': apply H or H**T from the Right
TRANS
TRANS is CHARACTER*1 = 'N': apply H (No transpose) = 'C': apply H**T (Transpose)
DIRECT
DIRECT is CHARACTER*1 Indicates how H is formed from a product of elementary reflectors = 'F': H = H(1) H(2) . . . H(k) (Forward, not supported yet) = 'B': H = H(k) . . . H(2) H(1) (Backward)
STOREV
STOREV is CHARACTER*1 Indicates how the vectors which define the elementary reflectors are stored: = 'C': Columnwise (not supported yet) = 'R': Rowwise
M
M is INTEGER The number of rows of the matrix C.
N
N is INTEGER The number of columns of the matrix C.
K
K is INTEGER The order of the matrix T (= the number of elementary reflectors whose product defines the block reflector).
L
L is INTEGER The number of columns of the matrix V containing the meaningful part of the Householder reflectors. If SIDE = 'L', M >= L >= 0, if SIDE = 'R', N >= L >= 0.
V
V is DOUBLE PRECISION array, dimension (LDV,NV). If STOREV = 'C', NV = K; if STOREV = 'R', NV = L.
LDV
LDV is INTEGER The leading dimension of the array V. If STOREV = 'C', LDV >= L; if STOREV = 'R', LDV >= K.
T
T is DOUBLE PRECISION array, dimension (LDT,K) The triangular K-by-K matrix T in the representation of the block reflector.
LDT
LDT is INTEGER The leading dimension of the array T. LDT >= K.
C
C is DOUBLE PRECISION array, dimension (LDC,N) On entry, the M-by-N matrix C. On exit, C is overwritten by H*C or H**T*C or C*H or C*H**T.
LDC
LDC is INTEGER The leading dimension of the array C. LDC >= max(1,M).
WORK
WORK is DOUBLE PRECISION array, dimension (LDWORK,K)
LDWORK
LDWORK is INTEGER The leading dimension of the array WORK. If SIDE = 'L', LDWORK >= max(1,N); if SIDE = 'R', LDWORK >= max(1,M).
- Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
- Contributors:
A. Petitet, Computer Science Dept., Univ. of Tenn., Knoxville, USA
Further Details:
Definition at line 181 of file dlarzb.f.
Author
Generated automatically by Doxygen for LAPACK from the source code.
Referenced By
The man page dlarzb(3) is an alias of dlarzb.f(3).
Tue Nov 28 2023 12:08:42 Version 3.12.0 LAPACK