NAME

SLARF - applie a real elementary reflector H to a real m by n matrix C, from either the left or the right

SYNOPSIS

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

CHARACTER SIDE

INTEGER INCV, LDC, M, N

REAL TAU

REAL C( LDC, ∗ ), V( ∗ ), WORK( ∗ )

PURPOSE

SLARF applies a real elementary reflector H to a real 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 real scalar and v is a real vector.
 
If tau = 0, then H is taken to be the unit matrix.
 

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) REAL 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) REAL
The value tau in the representation of H.

C       (input/output) REAL 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) REAL array, dimension
(N) if SIDE = ’L’ or (M) if SIDE = ’R’

  —  LAPACK version 2.0  —  08 October 1994