DLARZB (3) Linux Manual Page

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 (characterSIDE, characterTRANS, characterDIRECT, characterSTOREV, integerM, integerN, integerK, integerL, double precision, dimension( ldv, * )V, integerLDV, double precision, dimension( ldt, * )T, integerLDT, double precision, dimension( ldc, * )C, integerLDC, double precision, dimension( ldwork, * )WORK, integerLDWORK)

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.

Date:

September 2012

Contributors:

A. Petitet, Computer Science Dept., Univ. of Tenn., Knoxville, USA

Further Details:

 

Definition at line 183 of file dlarzb.f.

Author

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