Mercurial > octave
view scripts/linear-algebra/rank.m @ 2303:5cffc4b8de57
[project @ 1996-06-24 09:15:24 by jwe]
author | jwe |
---|---|
date | Mon, 24 Jun 1996 09:15:24 +0000 |
parents | 5d29638dd524 |
children | 2b5788792cad |
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### Copyright (C) 1996 John W. Eaton ### ### 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 ### 02111-1307, USA. function retval = rank (A, tol) ## usage: rank (a, tol) ## ## Return the rank of the matrix a. The rank is taken to be the number ## of singular values of a that are greater than tol. ## ## If the second argument is omitted, it is taken to be ## ## tol = max (size (a)) * sigma (1) * eps; ## ## where eps is machine precision and sigma is the largest singular ## value of a. if (nargin == 1) sigma = svd (A); tolerance = max (size (A)) * sigma (1) * eps; elseif (nargin == 2) sigma = svd (A); tolerance = tol; else usage ("rank (A)"); endif retval = sum (sigma > tolerance); endfunction