Mercurial > octave-nkf
view scripts/statistics/base/ranks.m @ 4960:ce01dbd7e026 ss-2-1-58
[project @ 2004-09-02 03:47:49 by jwe]
author | jwe |
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date | Thu, 02 Sep 2004 03:47:49 +0000 |
parents | a0f2839f6ac8 |
children | 4c8a2e4e0717 |
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## Copyright (C) 1995, 1996, 1997 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 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. ## -*- texinfo -*- ## @deftypefn {Function File} {} ranks (@var{x}, @var{dim}) ## If @var{x} is a vector, return the (column) vector of ranks of ## @var{x} adjusted for ties. ## ## If @var{x} is a matrix, do the above for along the first ## non-singleton dimension. If the optional argument @var{dim} is ## given, operate along this dimension. ## @end deftypefn ## Author: KH <Kurt.Hornik@ci.tuwien.ac.at> ## Description: Compute ranks ## This code was rather ugly, since it didn't use sort due to the ## fact of how to deal with ties. Now it does use sort and its ## even uglier!!! At least it handles NDArrays.. function y = ranks (x, dim) if (nargin != 1 && nargin != 2) usage ("ranks (x, dim)"); endif nd = ndims (x); sz = size (x); if (nargin != 2) ## Find the first non-singleton dimension. dim = 1; while (dim < nd + 1 && sz(dim) == 1) dim = dim + 1; endwhile if (dim > nd) dim = 1; endif else if (! (isscalar (dim) && dim == round (dim)) && dim > 0 && dim < (nd + 1)) error ("ranks: dim must be an integer and valid dimension"); endif endif if (sz(dim) == 1) y = ones(sz); else ## The algorithm works only on dim=1, so permute if necesary if (dim != 1) perm = [1 : nd]; perm(1) = dim; perm(dim) = 1; x = permute (x, perm); endif sz = size (x); infvec = -Inf * ones ([1, sz(2 : end)]); [xs, xi] = sort (x); eq_el = find (diff ([xs; infvec]) == 0); if (isempty (eq_el)) [eq_el, y] = sort (xi); else runs = complement (eq_el+1, eq_el); len = diff (find (diff ([Inf; eq_el; -Inf]) != 1)) + 1; [eq_el, y] = sort (xi); for i = 1 : length(runs) y (xi (runs (i) + [0:(len(i)-1)]) + floor (runs (i) ./ sz(1)) * sz(1)) = eq_el(runs(i)) + (len(i) - 1) / 2; endfor endif if (dim != 1) y = permute (y, perm); endif endif endfunction