update packages

[CreaPhase.git] / octave_packages / m / signal / sinc.m

diff --git a/octave_packages/m/signal/sinc.m b/octave_packages/m/signal/sinc.m
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+++ b/octave_packages/m/signal/sinc.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} {} sinc (@var{x})
+## Return
+## @tex
+## $ \sin (\pi x)/(\pi x)$.
+## @end tex
+## @ifnottex
+##  sin(pi*x)/(pi*x).
+## @end ifnottex
+## @end deftypefn
+
+## Author: jwe ???
+
+function result = sinc (x)
+
+  if (nargin != 1)
+    print_usage ();
+  endif
+
+  result = ones (size (x));
+
+  i = (x != 0);
+
+  if (any (i(:)))
+    t = pi * x(i);
+    result(i) = sin (t) ./ t;
+  endif
+
+endfunction
+
+
+%!assert (sinc (0), 1);
+%!assert (sinc (1), 0,1e-6);
+%!assert (sinc (1/2), 2/pi, 1e-6)
+
+%!error sinc()