update packages

[CreaPhase.git] / octave_packages / m / statistics / base / zscore.m

diff --git a/octave_packages/m/statistics/base/zscore.m b/octave_packages/m/statistics/base/zscore.m
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+## Copyright (C) 1995-2012 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 z = zscore (x, dim)
+
+  if (nargin != 1 && nargin != 2)
+    print_usage ();
+  endif
+
+  if (! (isnumeric (x) || islogical (x)))
+    error ("zscore: X must be a numeric vector or matrix");
+  endif
+
+  nd = ndims (x);
+  sz = size (x);
+  if (nargin != 2)
+    ## Find the first non-singleton dimension.
+    (dim = find (sz > 1, 1)) || (dim = 1);
+  else
+    if (!(isscalar (dim) && dim == fix (dim))
+        || !(1 <= dim && dim <= nd))
+      error ("zscore: DIM must be an integer and a valid dimension");
+    endif
+  endif
+
+  n = sz(dim);
+  if (n == 0)
+    z = x;
+  else
+    x = center (x, dim); # center also promotes integer to double for next line
+    z = zeros (sz, class (x));
+    s = std (x, [], dim);
+    s(s==0) = 1;
+    z = bsxfun (@rdivide, x, s);
+  endif
+
+endfunction
+
+
+%!assert(zscore ([1,2,3]), [-1,0,1])
+%!assert(zscore (single([1,2,3])), single([-1,0,1]))
+%!assert(zscore (int8([1,2,3])), [-1,0,1])
+%!assert(zscore (ones (3,2,2,2)), zeros (3,2,2,2))
+%!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 (['A'; 'B'])
+%!error zscore (1, ones(2,2))
+%!error zscore (1, 1.5)
+%!error zscore (1, 0)
+%!error zscore (1, 3)
+