Mercurial > octave-nkf
diff scripts/statistics/base/zscore.m @ 12586:f9b7aa3b88f8
Deprecate studentize(), replace with zscore().
author | Rik <octave@nomad.inbox5.com> |
---|---|
date | Fri, 08 Apr 2011 20:15:19 -0700 |
parents | scripts/statistics/base/studentize.m@c792872f8942 |
children | 6b2f14af2360 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/scripts/statistics/base/zscore.m Fri Apr 08 20:15:19 2011 -0700 @@ -0,0 +1,88 @@ +## Copyright (C) 1995-2011 Kurt Hornik +## +## 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} {} zscore (@var{x}) +## @deftypefnx {Function File} {} zscore (@var{x}, @var{dim}) +## If @var{x} is a vector, subtract its mean and divide by its standard +## deviation. +## +## If @var{x} is a matrix, do the above along the first non-singleton +## dimension. +## If the optional argument @var{dim} is given, operate along this dimension. +## @seealso{center} +## @end deftypefn + +## Author: KH <Kurt.Hornik@wu-wien.ac.at> +## Description: Subtract mean and divide by standard deviation + +function t = zscore (x, dim) + + if (nargin != 1 && nargin != 2) + print_usage (); + endif + + if (! isnumeric(x)) + error ("zscore: 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 ("zscore: DIM must be an integer and a valid dimension"); + endif + endif + + c = sz(dim); + if (c == 0) + t = x; + else + idx = ones (1, nd); + idx(dim) = c; + t = x - repmat (mean (x, dim), idx); + t = t ./ repmat (max (cat (dim, std(t, [], dim), ! any (t, dim)), [], dim), idx); + endif + +endfunction + +%!assert(zscore ([1,2,3]), [-1,0,1]) +%!assert(zscore (int8 ([1,2,3])), [-1,0,1]) +#%!assert(zscore (ones (3,2,0,2)), zeros (3,2,0,2)) +%!assert(zscore ([2,0,-2;0,2,0;-2,-2,2]), [1,0,-1;0,1,0;-1,-1,1]) + +%% Test input validation +%!error zscore () +%!error zscore (1, 2, 3) +%!error zscore ([true true]) +%!error zscore (1, ones(2,2)) +%!error zscore (1, 1.5) +%!error zscore (1, 0) +%!error zscore (1, 3) +