Mercurial > octave-nkf
view scripts/control/util/zgshsr.m @ 7125:f084ba47812b
[project @ 2007-11-08 02:29:23 by jwe]
author | jwe |
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date | Thu, 08 Nov 2007 02:29:24 +0000 |
parents | a1dbe9d80eee |
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## Copyright (C) 1996, 2000, 2002, 2003, 2004, 2005, 2007 ## 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 3 of the License, 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, see ## <http://www.gnu.org/licenses/>. ## -*- texinfo -*- ## @deftypefn {Function File} {@var{x} =} zgshsr (@var{y}) ## Apply householder vector based on ## @iftex ## @tex ## $ e^m $ ## @end tex ## @end iftex ## @ifinfo ## @math{e^(m)} ## @end ifinfo ## to column vector @var{y}. ## Called by @command{zgfslv}. ## @end deftypefn ## Author: A. S. Hodel <a.s.hodel@eng.auburn.edu> ## Created: July 24, 1992 ## Conversion to Octave by R. Bruce Tenison July 3, 1994 function x = zgshsr (y) if (nargin != 1) print_usage (); endif if (! isvector (y)) error ("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 /= (m + sqrt (m)); x(1) -= (beta * (1 + sqrt (m))); x(2:m) -= (beta * ones (m-1,1)); else x = -x; endif endfunction