slarfgp.f (3) - Linux Manuals
NAME
slarfgp.f -
SYNOPSIS
Functions/Subroutines
subroutine slarfgp (N, ALPHA, X, INCX, TAU)
SLARFGP generates an elementary reflector (Householder matrix) with non-negatibe beta.
Function/Subroutine Documentation
subroutine slarfgp (integerN, realALPHA, real, dimension( * )X, integerINCX, realTAU)
SLARFGP generates an elementary reflector (Householder matrix) with non-negatibe beta.
Purpose:
-
SLARFGP generates a real elementary reflector H of order n, such that H * ( alpha ) = ( beta ), H**T * H = I. ( x ) ( 0 ) where alpha and beta are scalars, beta is non-negative, and x is an (n-1)-element real vector. H is represented in the form H = I - tau * ( 1 ) * ( 1 v**T ) , ( v ) where tau is a real scalar and v is a real (n-1)-element vector. If the elements of x are all zero, then tau = 0 and H is taken to be the unit matrix.
Parameters:
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N
N is INTEGER The order of the elementary reflector.
ALPHAALPHA is REAL On entry, the value alpha. On exit, it is overwritten with the value beta.
XX is REAL array, dimension (1+(N-2)*abs(INCX)) On entry, the vector x. On exit, it is overwritten with the vector v.
INCXINCX is INTEGER The increment between elements of X. INCX > 0.
TAUTAU is REAL The value tau.
Author:
-
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date:
- September 2012
Definition at line 105 of file slarfgp.f.
Author
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