update packages

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

diff --git a/octave_packages/m/statistics/base/runlength.m b/octave_packages/m/statistics/base/runlength.m
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+## Copyright (C) 2005-2012 Paul Kienzle
+##
+## 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} {[count, value] =} runlength (@var{x})
+## Find the lengths of all sequences of common values.  Return the
+## vector of lengths and the value that was repeated.
+##
+## @example
+## @group
+## runlength ([2, 2, 0, 4, 4, 4, 0, 1, 1, 1, 1])
+## @result{}  [2, 1, 3, 1, 4]
+## @end group
+## @end example
+## @end deftypefn
+
+function [count, value] = runlength (x)
+
+  if (nargin != 1)
+    print_usage ();
+  endif
+
+  if (!(isnumeric (x) || islogical (x)) || !isvector (x))
+    error ("runlength: X must be a numeric vector");
+  endif
+
+  if (iscolumn (x))
+    x = x.';
+  endif
+
+  idx = [find(x(1:end-1) != x(2:end)), length(x)];
+  count = diff ([0 idx]);
+  if (nargout == 2)
+    value = x(idx);
+  endif
+
+endfunction
+
+
+%!assert (runlength([2 2 0 4 4 4 0 1 1 1 1]), [2 1 3 1 4]);
+%!assert (runlength([2 2 0 4 4 4 0 1 1 1 1]'), [2 1 3 1 4]);
+%!test
+%! [c, v] = runlength ([2 2 0 4 4 4 0 1 1 1 1]);
+%! assert (c, [2 1 3 1 4]);
+%! assert (v, [2 0 4 0 1]);
+
+%% Test input validation
+%!error runlength ()
+%!error runlength (1, 2)
+%!error runlength (['A'; 'B'])
+%!error runlength (ones(2,2))