update packages

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

diff --git a/octave_packages/m/statistics/base/ranks.m b/octave_packages/m/statistics/base/ranks.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} {} ranks (@var{x}, @var{dim})
+## Return the ranks of @var{x} along the first non-singleton dimension
+## adjusted for ties.  If the optional argument @var{dim} is
+## given, operate along this dimension.
+## @seealso{spearman, kendall}
+## @end deftypefn
+
+## Author: KH <Kurt.Hornik@wu-wien.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)
+    print_usage ();
+  endif
+
+  if (! (isnumeric (x) || islogical (x)))
+    error ("ranks: 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 ("ranks: DIM must be an integer and a 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 ([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 = setdiff (eq_el, eq_el+1);
+      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
+
+
+%!assert(ranks (1:2:10), 1:5);
+%!assert(ranks (10:-2:1), 5:-1:1);
+%!assert(ranks ([2, 1, 2, 4]), [2.5, 1, 2.5, 4]);
+%!assert(ranks (ones(1, 5)), 3*ones(1, 5));
+%!assert(ranks (1e6*ones(1, 5)), 3*ones(1, 5));
+%!assert(ranks (rand (1, 5), 1), ones(1, 5));
+
+%% Test input validation
+%!error ranks ()
+%!error ranks (1, 2, 3)
+%!error ranks ({1, 2})
+%!error ranks (['A'; 'B'])
+%!error ranks (1, 1.5)
+%!error ranks (1, 0)
+%!error ranks (1, 3)
+