slarfx.f File Reference

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Functions/Subroutines
subroutine	slarfx (SIDE, M, N, V, TAU, C, LDC, WORK)
	SLARFX applies an elementary reflector to a general rectangular matrix, with loop unrolling when the reflector has order ≤ 10.

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Function/Subroutine Documentation

subroutine slarfx	(	character	SIDE,
		integer	M,
		integer	N,
		real, dimension( * )	V,
		real	TAU,
		real, dimension( ldc, * )	C,
		integer	LDC,
		real, dimension( * )	WORK
	)

SLARFX applies an elementary reflector to a general rectangular matrix, with loop unrolling when the reflector has order ≤ 10.

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

Purpose:

 SLARFX 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

 This version uses inline code if H has order < 11.

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 (M) if SIDE = 'L' or (N) if SIDE = 'R' The vector v in the representation of H.
[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. LDA >= (1,M).
[out]	WORK	WORK is REAL array, dimension (N) if SIDE = 'L' or (M) if SIDE = 'R' WORK is not referenced if H has order < 11.

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

September 2012

Definition at line 121 of file slarfx.f.

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