Mercurial > hg > octave-nkf
view scripts/signal/ifftshift.m @ 6207:3c92b8d892dd
[project @ 2006-12-06 20:19:14 by dbateman]
author | dbateman |
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date | Wed, 06 Dec 2006 20:19:16 +0000 |
parents | 34f96dd5441b |
children | 93c65f2a5668 |
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## Copyright (C) 1997 by Vincent Cautaerts ## ## 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 2, 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, write to the Free ## Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA ## 02110-1301, USA. ## -*- texinfo -*- ## @deftypefn {Function File} {} ifftshift (@var{v}) ## @deftypefnx {Function File} {} ifftshift (@var{v}, @var{dim}) ## Undo the action of the @code{fftshift} function. For even length ## @var{v}, @code{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 ## Modified-By: David Bateman, add NDArray capability and option dim arg function retval = ifftshift (V, dim) retval = 0; if (nargin != 1 && nargin != 2) print_usage (); endif if (nargin == 2) if (!isscalar (dim)) error ("ifftshift: dimension must be an integer scalar"); endif nd = ndims (V); sz = size (V); sz2 = floor (sz(dim) / 2); idx = cell (); for i=1:nd idx {i} = 1:sz(i); endfor idx {dim} = [sz2+1:sz(dim), 1:sz2]; retval = V (idx{:}); else if (isvector (V)) x = length (V); xx = floor (x/2); retval = V([xx+1:x, 1:xx]); elseif (ismatrix (V)) nd = ndims (V); sz = size (V); sz2 = floor (sz ./ 2); idx = cell (); for i=1:nd idx{i} = [sz2(i)+1:sz(i), 1:sz2(i)]; endfor retval = V (idx{:}); else error ("ifftshift: expecting vector or matrix argument"); endif endif endfunction