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zlarz.f(3) LAPACK zlarz.f(3)

NAME

zlarz.f -

SYNOPSIS

Functions/Subroutines


subroutine zlarz (SIDE, M, N, L, V, INCV, TAU, C, LDC, WORK)
 
ZLARZ applies an elementary reflector (as returned by stzrzf) to a general matrix.

Function/Subroutine Documentation

subroutine zlarz (characterSIDE, integerM, integerN, integerL, complex*16, dimension( * )V, integerINCV, complex*16TAU, complex*16, dimension( ldc, * )C, integerLDC, complex*16, dimension( * )WORK)

ZLARZ applies an elementary reflector (as returned by stzrzf) to a general matrix.
Purpose:
 ZLARZ applies a complex elementary reflector H to a complex
 M-by-N matrix C, from either the left or the right. H is represented
 in the form
H = I - tau * v * v**H
where tau is a complex scalar and v is a complex vector.
If tau = 0, then H is taken to be the unit matrix.
To apply H**H (the conjugate transpose of H), supply conjg(tau) instead tau.
H is a product of k elementary reflectors as returned by ZTZRZF.
Parameters:
SIDE
          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 COMPLEX*16 array, dimension (1+(L-1)*abs(INCV))
          The vector v in the representation of H as returned by
          ZTZRZF. V is not used if TAU = 0.
INCV
          INCV is INTEGER
          The increment between elements of v. INCV <> 0.
TAU
          TAU is COMPLEX*16
          The value tau in the representation of H.
C
          C is COMPLEX*16 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 COMPLEX*16 array, dimension
                         (N) if SIDE = 'L'
                      or (M) if SIDE = 'R'
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 148 of file zlarz.f.

Author

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