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view main/general/ifftshift.m @ 0:6b33357c7561 octave-forge
Initial revision
author | pkienzle |
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date | Wed, 10 Oct 2001 19:54:49 +0000 |
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children | 9a986e3452a4 |
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## Copyright (C) 1997 by Vincent Cautaerts ## ## 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 2, 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 file. If not, write to the Free Software Foundation, ## 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. ## -*- texinfo -*- ## @deftypefn {Function File} {} ifftshift (@var{v}) ## Undo the action of the fftshift function. For even length @var{v}, fftshift ## is its own inverse, but odd lengths differ slightly. ## @end deftypefn ## Author: Vincent Cautaerts <vincent@comf5.comm.eng.osaka-u.ac.jp> ## Created: July 1997 ## Adapted-By: jwe ## Modified-By: Paul Kienzle, converted from fftshift function retval = ifftshift (V) retval = 0; if (nargin != 1) usage ("usage: ifftshift (X)"); endif if (is_vector (V)) x = length (V); xx = floor (x/2); retval = V([xx+1:x, 1:xx]); elseif (is_matrix (V)) [x, y] = size (V); xx = floor (x/2); yy = floor (y/2); retval = V([xx+1:x, 1:xx], [yy+1:y, 1:yy]); else error ("ifftshift: expecting vector or matrix argument"); endif endfunction