dlarfb (l)  Linux Manuals
dlarfb: applies a real block reflector H or its transpose Haq to a real m by n matrix C, from either the left or the right
Command to display dlarfb
manual in Linux: $ man l dlarfb
NAME
DLARFB  applies a real block reflector H or its transpose Haq to a real m by n matrix C, from either the left or the right
SYNOPSIS
 SUBROUTINE DLARFB(

SIDE, TRANS, DIRECT, STOREV, M, N, K, V, LDV,
T, LDT, C, LDC, WORK, LDWORK )

IMPLICIT
NONE

CHARACTER
DIRECT, SIDE, STOREV, TRANS

INTEGER
K, LDC, LDT, LDV, LDWORK, M, N

DOUBLE
PRECISION C( LDC, * ), T( LDT, * ), V( LDV, * ),
WORK( LDWORK, * )
PURPOSE
DLARFB applies a real block reflector H or its transpose Haq to a
real m by n matrix C, from either the left or the right.
ARGUMENTS
 SIDE (input) CHARACTER*1

= aqLaq: apply H or Haq from the Left
= aqRaq: apply H or Haq from the Right
 TRANS (input) CHARACTER*1

= aqNaq: apply H (No transpose)
= aqTaq: apply Haq (Transpose)
 DIRECT (input) CHARACTER*1

Indicates how H is formed from a product of elementary
reflectors
= aqFaq: H = H(1) H(2) . . . H(k) (Forward)
= aqBaq: H = H(k) . . . H(2) H(1) (Backward)
 STOREV (input) CHARACTER*1

Indicates how the vectors which define the elementary
reflectors are stored:
= aqCaq: Columnwise
= aqRaq: Rowwise
 M (input) INTEGER

The number of rows of the matrix C.
 N (input) INTEGER

The number of columns of the matrix C.
 K (input) INTEGER

The order of the matrix T (= the number of elementary
reflectors whose product defines the block reflector).
 V (input) DOUBLE PRECISION array, dimension

(LDV,K) if STOREV = aqCaq
(LDV,M) if STOREV = aqRaq and SIDE = aqLaq
(LDV,N) if STOREV = aqRaq and SIDE = aqRaq
The matrix V. See further details.
 LDV (input) INTEGER

The leading dimension of the array V.
If STOREV = aqCaq and SIDE = aqLaq, LDV >= max(1,M);
if STOREV = aqCaq and SIDE = aqRaq, LDV >= max(1,N);
if STOREV = aqRaq, LDV >= K.
 T (input) DOUBLE PRECISION array, dimension (LDT,K)

The triangular k by k matrix T in the representation of the
block reflector.
 LDT (input) INTEGER

The leading dimension of the array T. LDT >= K.
 C (input/output) DOUBLE PRECISION array, dimension (LDC,N)

On entry, the m by n matrix C.
On exit, C is overwritten by H*C or Haq*C or C*H or C*Haq.
 LDC (input) INTEGER

The leading dimension of the array C. LDA >= max(1,M).
 WORK (workspace) DOUBLE PRECISION array, dimension (LDWORK,K)

 LDWORK (input) INTEGER

The leading dimension of the array WORK.
If SIDE = aqLaq, LDWORK >= max(1,N);
if SIDE = aqRaq, LDWORK >= max(1,M).
Pages related to dlarfb
 dlarfb (3)
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 dlarfg (l)  generates a real elementary reflector H of order n, such that H * ( alpha ) = ( beta ), Haq * H = I
 dlarfp (l)  generates a real elementary reflector H of order n, such that H * ( alpha ) = ( beta ), Haq * H = I
 dlarft (l)  forms the triangular factor T of a real block reflector H of order n, which is defined as a product of k elementary reflectors
 dlarfx (l)  applies a real elementary reflector H to a real m by n matrix C, from either the left or the right
 dlar1v (l)  computes the (scaled) rth column of the inverse of the sumbmatrix in rows B1 through BN of the tridiagonal matrix L D L^T  sigma I
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 dlargv (l)  generates a vector of real plane rotations, determined by elements of the real vectors x and y
 dlarnv (l)  returns a vector of n random real numbers from a uniform or normal distribution