Mercurial > octave
view scripts/control/zgshsr.m @ 3381:69b167451491
[project @ 1999-12-15 20:48:10 by jwe]
author | jwe |
---|---|
date | Wed, 15 Dec 1999 20:48:45 +0000 |
parents | 8dd4718801fd |
children | 10f21f7ccc7f |
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## Copyright (C) 1996 Auburn University. All Rights Reserved ## ## This file is part of Octave. ## ## Octave is free software; you can redistribute it and/or modify it ## under the terms of the GNU General Public License as published by the ## Free Software Foundation; either version 2, or (at your option) any ## later version. ## ## Octave is distributed in the hope that it will be useful, but WITHOUT ## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or ## FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License ## for more details. ## ## You should have received a copy of the GNU General Public License ## along with Octave; see the file COPYING. If not, write to the Free ## Software Foundation, 59 Temple Place, Suite 330, Boston, MA 02111 USA. ## -*- texinfo -*- ## @deftypefn {Function File } { @var{x} =} zgshsr( @var{y}) ## apply householder vector based on @math{e^(m)} to ## (column vector) y. ## Called by zgfslv ## @end deftypefn function x = zgshsr(y) ## A. S. Hodel July 24, 1992 ## Conversion to Octave by R. Bruce Tenison July 3, 1994 if(!is_vector(y)) error(sprintf("y(%dx%d) must be a vector",rows(y),columns(y))); endif x = vec(y); m = length(x); if (m>1) beta = (1 + sqrt(m))*x(1) + sum(x(2:m)); beta = beta/(m+sqrt(m)); x(1) = x(1) - beta*(1.0d0+sqrt(m)); x(2:m) = x(2:m) - beta*ones(m-1,1); else x = -x; endif endfunction