octave:scripts/statistics/base/ranks.m

changelog shortlog tags changeset files revisions annotate raw

scripts/statistics/base/ranks.m

changeset 10289:	4b124317dc38
parent:	eb63fbe60fab
author:	John W. Eaton <jwe@octave.org>
date:	Tue Feb 09 20:58:55 2010 -0500 (29 minutes ago)
permissions:	-rw-r--r--
description:	base_properties::set_children: account for hidden children

     1## Copyright (C) 1995, 1996, 1997, 1998, 2000, 2002, 2004, 2005, 2006,
     2##               2007, 2008, 2009 Kurt Hornik
     3##
     4## This file is part of Octave.
     5##
     6## Octave is free software; you can redistribute it and/or modify it
     7## under the terms of the GNU General Public License as published by
     8## the Free Software Foundation; either version 3 of the License, or (at
     9## your option) any later version.
    10##
    11## Octave is distributed in the hope that it will be useful, but
    12## WITHOUT ANY WARRANTY; without even the implied warranty of
    13## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    14## General Public License for more details.
    15##
    16## You should have received a copy of the GNU General Public License
    17## along with Octave; see the file COPYING.  If not, see
    18## <http://www.gnu.org/licenses/>.
    19
    20## -*- texinfo -*-
    21## @deftypefn {Function File} {} ranks (@var{x}, @var{dim})
    22## Return the ranks of @var{x} along the first non-singleton dimension
    23## adjust for ties.  If the optional argument @var{dim} is
    24## given, operate along this dimension.
    25## @end deftypefn
    26
    27## Author: KH <Kurt.Hornik@wu-wien.ac.at>
    28## Description: Compute ranks
    29
    30## This code was rather ugly, since it didn't use sort due to the
    31## fact of how to deal with ties. Now it does use sort and its
    32## even uglier!!! At least it handles NDArrays..
    33
    34function y = ranks (x, dim)
    35
    36  if (nargin != 1 && nargin != 2)
    37    print_usage ();
    38  endif
    39
    40  nd = ndims (x);
    41  sz = size (x);
    42  if (nargin != 2)
    43    ## Find the first non-singleton dimension.
    44    dim  = 1;
    45    while (dim < nd + 1 && sz(dim) == 1)
    46      dim = dim + 1;
    47    endwhile
    48    if (dim > nd)
    49      dim = 1;
    50    endif
    51  else
    52    if (! (isscalar (dim) && dim == round (dim))
    53	&& dim > 0
    54	&& dim < (nd + 1))
    55      error ("ranks: dim must be an integer and valid dimension");
    56    endif
    57  endif
    58
    59  if (sz(dim) == 1)
    60    y = ones(sz);
    61  else
    62    ## The algorithm works only on dim = 1, so permute if necesary.
    63    if (dim != 1)
    64      perm = [1 : nd];
    65      perm(1) = dim;
    66      perm(dim) = 1;
    67      x = permute (x, perm);
    68    endif
    69    sz = size (x);
    70    infvec = -Inf * ones ([1, sz(2 : end)]);
    71    [xs, xi] = sort (x);
    72    eq_el = find (diff ([xs; infvec]) == 0);
    73    if (isempty (eq_el))
    74      [eq_el, y] = sort (xi);
    75    else
    76      runs = complement (eq_el+1, eq_el);
    77      len = diff (find (diff ([Inf; eq_el; -Inf]) != 1)) + 1;
    78      [eq_el, y] = sort (xi);
    79      for i = 1 : length(runs)
    80	y (xi (runs (i) + [0:(len(i)-1)]) + floor (runs (i) ./ sz(1)) 
    81	   * sz(1)) = eq_el(runs(i)) + (len(i) - 1) / 2;
    82      endfor
    83    endif  
    84    if (dim != 1)
    85      y = permute (y, perm);
    86    endif
    87  endif
    88
    89endfunction