[Octave-cvsupdate] SF.net SVN: octave:[10137] trunk/octave-forge/extra/control-devel/inst/@ iddata/fft.m

[<par...@us...>]

Revision: 10137
          http://octave.svn.sourceforge.net/octave/?rev=10137&view=rev
Author:   paramaniac
Date:     2012-04-03 13:55:17 +0000 (Tue, 03 Apr 2012)
Log Message:
-----------
control-devel: add early draft file for fft method

Added Paths:
-----------
    trunk/octave-forge/extra/control-devel/inst/@iddata/fft.m

Added: trunk/octave-forge/extra/control-devel/inst/@iddata/fft.m
===================================================================
--- trunk/octave-forge/extra/control-devel/inst/@iddata/fft.m	                        (rev 0)
+++ trunk/octave-forge/extra/control-devel/inst/@iddata/fft.m	2012-04-03 13:55:17 UTC (rev 10137)
@@ -0,0 +1,59 @@
+## Copyright (C) 2012   Lukas F. Reichlin
+##
+## This file is part of LTI Syncope.
+##
+## LTI Syncope 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.
+##
+## LTI Syncope 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 LTI Syncope.  If not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {@var{dat} =} fft (@var{dat})
+## @deftypefnx {Function File} {@var{dat} =} fft (@var{dat}, @var{ord})
+## Detrend outputs and inputs of dataset @var{dat} by
+## removing the best fit of a polynomial of order @var{ord}.
+## If @var{ord} is not specified, default value 0 is taken.
+## This corresponds to removing a constant.
+## @end deftypefn
+
+## Author: Lukas Reichlin <luk...@gm...>
+## Created: April 2012
+## Version: 0.1
+
+function dat = fft (dat, n)
+
+  if (nargin > 2)       # no need to test nargin == 0, this is handled by built-in fft
+    print_usage ();
+  endif
+
+%  if ((! is_real_scalar (ord) || fix (ord) != ord) && ! ischar (ord))   # chars are handled by built-in detrend
+%    error ("iddata: detrend: second argument must be a positve integer");
+%  endif
+
+  dat.y = cellfun (@fft, dat.y, "uniformoutput", false);
+  dat.u = cellfun (@fft, dat.u, "uniformoutput", false);
+  
+  dat.timedomain = false;
+
+%  dat.y = cellfun (@(y) fft (y, n), dat.y, "uniformoutput", false);
+%  dat.u = cellfun (@(u) fft (u, n), dat.u, "uniformoutput", false);
+
+endfunction
+
+
+%!shared DATD, Z
+%! DAT = iddata ({[(1:10).', (1:2:20).'], [(10:-1:1).', (20:-2:1).']}, {[(41:50).', (46:55).'], [(61:70).', (-66:-1:-75).']});
+%! DATD = detrend (DAT, "linear");
+%! Z = zeros (10, 2);
+%!assert (DATD.y{1}, Z, 1e-10);
+%!assert (DATD.y{2}, Z, 1e-10);
+%!assert (DATD.u{1}, Z, 1e-10);
+%!assert (DATD.u{2}, Z, 1e-10);

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