slarf.f File Reference

Functions/Subroutines
subroutine	slarf (side, m, n, v, incv, tau, c, ldc, work)
	SLARF

Function/Subroutine Documentation

slarf()

subroutine slarf	(	character	side,
		integer	m,
		integer	n,
		real, dimension( * )	v,
		integer	incv,
		real	tau,
		real, dimension( ldc, * )	c,
		integer	ldc,
		real, dimension( * )	work
	)

SLARF

Download SLARF + dependencies [TGZ] [ZIP] [TXT]

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**T

 where tau is a real scalar and v is a real vector.

 If tau = 0, then H is taken to be the unit matrix.

Parameters

[in]	SIDE	SIDE is CHARACTER*1 = 'L': form H * C = 'R': form C * H
[in]	M	M is INTEGER The number of rows of the matrix C.
[in]	N	N is INTEGER The number of columns of the matrix C.
[in]	V	V is 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.
[in]	INCV	INCV is INTEGER The increment between elements of v. INCV <> 0.
[in]	TAU	TAU is REAL The value tau in the representation of H.
[in,out]	C	C is 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'.
[in]	LDC	LDC is INTEGER The leading dimension of the array C. LDC >= max(1,M).
[out]	WORK	WORK is REAL 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

November 2011