Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / signal-1.1.3 / dwt.m

diff --git a/octave_packages/signal-1.1.3/dwt.m b/octave_packages/signal-1.1.3/dwt.m
new file mode 100644 (file)
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+++ b/octave_packages/signal-1.1.3/dwt.m
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+## Copyright (C) 2008 Sylvain Pelissier <sylvain.pelissier@gmail.com>
+##
+## This program 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.
+##
+## This program 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
+## this program; if not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {[@var{ca} @var{cd}] =} dwt(@var{x,lo_d,hi_d})
+## Comupte de discrete wavelet transform of x with one level.
+## @end deftypefn
+
+function [ca cd] = dwt(x,lo_d,hi_d)
+  if (nargin < 3|| nargin > 3)
+    print_usage;
+  elseif(~isvector(x)  || ~isvector(lo_d) || ~isvector(hi_d))
+    error('x, hi_d and lo_d must be vectors');
+  end
+
+  h = filter(hi_d,1,x);
+  g = filter(lo_d,1,x);
+
+  cd = downsample(h,2);
+  ca = downsample(g,2);
+endfunction