update packages

[CreaPhase.git] / octave_packages / m / signal / ifftshift.m

diff --git a/octave_packages/m/signal/ifftshift.m b/octave_packages/m/signal/ifftshift.m
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+## Copyright (C) 1997-2012 Vincent Cautaerts
+##
+## This file is part of Octave.
+##
+## 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 3 of the License, 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, see
+## <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn  {Function File} {} ifftshift (@var{x})
+## @deftypefnx {Function File} {} ifftshift (@var{x}, @var{dim})
+## Undo the action of the @code{fftshift} function.  For even length
+## @var{x}, @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 (x, 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 (x);
+    sz = size (x);
+    sz2 = floor (sz(dim) / 2);
+    idx = repmat ({':'}, nd, 1);
+    idx{dim} = [sz2+1:sz(dim), 1:sz2];
+    retval = x(idx{:});
+  else
+    if (isvector (x))
+      xl = length (x);
+      xx = floor (xl/2);
+      retval = x([xx+1:xl, 1:xx]);
+    elseif (ismatrix (x))
+      nd = ndims (x);
+      sz = size (x);
+      sz2 = floor (sz ./ 2);
+      idx = cell ();
+      for i = 1:nd
+        idx{i} = [sz2(i)+1:sz(i), 1:sz2(i)];
+      endfor
+      retval = x(idx{:});
+    else
+      error ("ifftshift: expecting vector or matrix argument");
+    endif
+  endif
+
+endfunction
+
+%!test
+%!  x = [0:7];
+%!  y = ifftshift (x);
+%!  assert(y, [4 5 6 7 0 1 2 3]);
+%!  assert(ifftshift (y), x);
+
+%!test
+%!  x = [0:6];
+%!  y = ifftshift (x);
+%!  assert(y, [3 4 5 6 0 1 2]);
+%!  assert(ifftshift (y), [6 0 1 2 3 4 5]);
+
+%!test
+%!  x = [0:7]';
+%!  y = ifftshift (x);
+%!  assert(y, [4;5;6;7;0;1;2;3]);
+%!  assert(ifftshift (y), x);
+
+%!test
+%!  x = [0:6]';
+%!  y = ifftshift (x);
+%!  assert(y, [3;4;5;6;0;1;2]);
+%!  assert(ifftshift (y), [6;0;1;2;3;4;5]);
+
+%!test
+%!  x = [0:3];
+%!  x = [x;2*x;3*x+1;4*x+1];
+%!  y = ifftshift (x);
+%!  assert(y, [[7 10 1 4];[9 13 1 5];[2 3 0 1];[4 6 0 2]]);
+%!  assert(ifftshift (y), x);
+
+%!test
+%!  x = [0:3];
+%!  x = [x;2*x;3*x+1;4*x+1];
+%!  y = ifftshift (x,1);
+%!  assert(y, [[1 4 7 10];[1 5 9 13];[0 1 2 3];[0 2 4 6]]);
+%!  assert(ifftshift (y,1), x);
+
+%!test
+%!  x = [0:3];
+%!  x = [x;2*x;3*x+1;4*x+1];
+%!  y = ifftshift (x,2);
+%!  assert(y, [[2 3 0 1];[4 6 0 2];[7 10 1 4];[9 13 1 5]]);
+%!  assert(ifftshift (y,2), x);
+