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view scripts/statistics/base/center.m @ 11523:fd0a3ac60b0e
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author | John W. Eaton <jwe@octave.org> |
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date | Fri, 14 Jan 2011 05:47:45 -0500 |
parents | e151e23f73bc |
children | f9b7aa3b88f8 |
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## Copyright (C) 1995-2011 Kurt Hornik ## Copyright (C) 2009 VZLU Prague ## ## 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} {} center (@var{x}) ## @deftypefnx {Function File} {} center (@var{x}, @var{dim}) ## If @var{x} is a vector, subtract its mean. ## If @var{x} is a matrix, do the above for each column. ## If the optional argument @var{dim} is given, operate along this dimension. ## @seealso{studentize} ## @end deftypefn ## Author: KH <Kurt.Hornik@wu-wien.ac.at> ## Description: Center by subtracting means function retval = center (x, dim) if (nargin != 1 && nargin != 2) print_usage (); endif if (!isnumeric (x)) error ("center: X must be a numeric vector or matrix"); endif if (isinteger (x)) x = double (x); endif nd = ndims (x); sz = size (x); if (nargin != 2) ## Find the first non-singleton dimension. dim = find (sz > 1, 1); if (isempty (dim)) dim = 1; endif else if (!(isscalar (dim) && dim == fix (dim)) || !(1 <= dim && dim <= nd)) error ("center: DIM must be an integer and a valid dimension"); endif endif n = size (x, dim); if (n == 0) retval = x; else retval = bsxfun (@minus, x, sum (x, dim) / n); endif endfunction %!assert(center ([1,2,3]), [-1,0,1]) %!assert(center (int8 ([1,2,3])), [-1,0,1]) %!assert(center (ones (3,2,0,2)), zeros (3,2,0,2)) %!assert(center (magic (3)), [3,-4,1;-2,0,2;-1,4,-3]) %% Test input validation %!error center () %!error center (1, 2, 3) %!error center ([true true]) %!error center (1, ones(2,2)) %!error center (1, 1.5) %!error center (1, 0) %!error center (1, 3)