--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/scripts/signal/ifftshift.m	Wed May 17 21:00:54 2006 +0000
@@ -0,0 +1,72 @@
+## 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)
+    usage ("usage: ifftshift (X, dim)");
+  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