update packages

[CreaPhase.git] / octave_packages / m / polynomial / polyreduce.m

diff --git a/octave_packages/m/polynomial/polyreduce.m b/octave_packages/m/polynomial/polyreduce.m
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+## Copyright (C) 1994-2012 John W. Eaton
+##
+## 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} {} polyreduce (@var{c})
+## Reduce a polynomial coefficient vector to a minimum number of terms by
+## stripping off any leading zeros.
+## @seealso{polyout}
+## @end deftypefn
+
+## Author: Tony Richardson <arichard@stark.cc.oh.us>
+## Created: June 1994
+## Adapted-By: jwe
+
+function p = polyreduce (c)
+
+  if (nargin != 1)
+    print_usage ();
+  endif
+
+  if (!isvector (c) || isempty (c))
+    error ("polyreduce: C must be a non-empty vector");
+  endif
+
+  if (! isempty (c))
+
+    index = find (c != 0);
+
+    if (isempty (index))
+
+      p = 0;
+
+    else
+
+      p = c(index (1):length (c));
+
+    endif
+
+  endif
+
+endfunction
+
+%!assert(all (all (polyreduce ([0, 0, 1, 2, 3]) == [1, 2, 3])));
+
+%!assert(all (all (polyreduce ([1, 2, 3, 0, 0]) == [1, 2, 3, 0, 0])));
+
+%!assert(all (all (polyreduce ([1, 0, 3]) == [1, 0, 3])));
+
+%!error polyreduce ([1, 2; 3, 4]);
+