update packages

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

diff --git a/octave_packages/m/signal/spencer.m b/octave_packages/m/signal/spencer.m
new file mode 100644 (file)
index 0000000..4ffd073
--- /dev/null
+++ b/octave_packages/m/signal/spencer.m
@@ -0,0 +1,53 @@
+## Copyright (C) 1995-2012 Friedrich Leisch
+##
+## 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} {} spencer (@var{x})
+## Return Spencer's 15 point moving average of each column of
+## @var{x}.
+## @end deftypefn
+
+## Author: FL <Friedrich.Leisch@ci.tuwien.ac.at>
+## Description: Apply Spencer's 15-point MA filter
+
+function retval = spencer (x)
+
+  if (nargin != 1)
+    print_usage ();
+  endif
+
+  [xr, xc] = size(x);
+
+  n = xr;
+  c = xc;
+
+  if (isvector(x))
+   n = length(x);
+   c = 1;
+   x = reshape(x, n, 1);
+  endif
+
+  w = [-3, -6, -5, 3, 21, 46, 67, 74, 67, 46, 21, 3, -5, -6, -3] / 320;
+
+  retval = fftfilt (w, x);
+  retval = [zeros(7,c); retval(15:n,:); zeros(7,c);];
+
+  retval = reshape(retval, xr, xc);
+
+endfunction
+