NAME

zlarf - applie a complex elementary reflector H to a complex M-by-N matrix C, from either the left or the right

SYNOPSIS

SUBROUTINE ZLARF(
SIDE, M, N, V, INCV, TAU, C, LDC, WORK )

void zlarf(char side, long int m, long int n, doublecomplex ∗v,
long int incv, doublecomplex ∗tau, doublecomplex ∗zc, long int ldc)

CHARACTER SIDE

INTEGER INCV, LDC, M, N

COMPLEX∗16 TAU

COMPLEX∗16 C( LDC, ∗ ), V( ∗ ), WORK( ∗ )

PURPOSE

ZLARF 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’
 
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’ (the conjugate transpose of H), supply conjg(tau) instead tau.
 

ARGUMENTS

SIDE    (input) CHARACTER∗1
= ’L’: form  H ∗ C
= ’R’: form  C ∗ H

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

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

V       (input) COMPLEX∗16 array, dimension
(1 + (M-1)∗abs(INCV)) if SIDE = ’L’ or (1 + (N-1)∗abs(INCV)) if SIDE = ’R’ The vector v in the representation of H. V is not used if TAU = 0.

INCV    (input) INTEGER
The increment between elements of v. INCV <> 0.

TAU     (input) COMPLEX∗16
The value tau in the representation of H.

C       (input/output) 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     (input) INTEGER
The leading dimension of the array C. LDC >= max(1,M).

WORK    (workspace) COMPLEX∗16 array, dimension
(N) if SIDE = ’L’ or (M) if SIDE = ’R’

Sun, Inc.  —  Last change: 20 Sep 1996