*** scripts/signal/fftshift.m.orig	2004-03-29 18:30:51.000000000 +0200
--- scripts/signal/fftshift.m	2004-03-29 18:37:10.000000000 +0200
***************
*** 19,24 ****
--- 19,25 ----
  
  ## -*- texinfo -*-
  ## @deftypefn {Function File} {} fftshift (@var{v})
+ ## @deftypefnx {Function File} {} fftshift (@var{v}, @var{dim})
  ## Perform a shift of the vector @var{v}, for use with the @code{fft}
  ## and @code{ifft} functions, in order the move the frequency 0 to the
  ## center of the vector or matrix.
***************
*** 31,62 ****
  ## f = ((1:N) - ceil(N/2)) / N / Dt
  ## @end example
  ##
! ## If @var{v} is a matrix, the same holds for rows and columns.
  ## @end deftypefn
  
  ## Author: Vincent Cautaerts <address@hidden>
  ## Created: July 1997
  ## Adapted-By: jwe
  
! function retval = fftshift (V)
  
    retval = 0;
  
!   if (nargin != 1)
!     usage ("usage: fftshift (X)");
    endif
  
!   if (isvector (V))
!     x = length (V);
!     xx = ceil (x/2);
!     retval = V([xx+1:x, 1:xx]);
!   elseif (ismatrix (V))
!     [x, y] = size (V);
!     xx = ceil (x/2);
!     yy = ceil (y/2);
!     retval = V([xx+1:x, 1:xx], [yy+1:y, 1:yy]);
    else
!     error ("fftshift: expecting vector or matrix argument");
    endif
  
  endfunction
--- 32,89 ----
  ## f = ((1:N) - ceil(N/2)) / N / Dt
  ## @end example
  ##
! ## If @var{v} is a matrix, the same holds for rows and columns. If 
! ## @var{v} is an array, then the same holds along each dimension.
! ##
! ## The optional @var{dim} argument can be used to limit the dimension
! ## along which the permutation occurs.
  ## @end deftypefn
  
  ## Author: Vincent Cautaerts <address@hidden>
  ## Created: July 1997
  ## Adapted-By: jwe
  
! function retval = fftshift (V, dim)
  
    retval = 0;
  
!   if (nargin != 1 && nargin != 2)
!     usage ("usage: fftshift (X, dim)");
    endif
  
!   if (nargin == 2)
!     if (!isscalar (dim))
!       error ("fftshift: dimension must be an integer scalar");
!     endif
!     nd = ndims (V);
!     szd = size (V, dim);
!     szd2 = ceil (szd / 2);
!     idx = repmat ( ":,", nd, 1);
!     idx (nd, : ) = ": ";
!     if (dim == nd)
!       idx (dim, :) = "[szd2+1:szd, 1:szd2]";
!     else
!       idx (dim, :) = "[szd2+1:szd, 1:szd2],";
!     endif
!     retval = eval ([" V (", transpose(transpose(idx)(:)), ");"]);
    else
!     if (isvector (V))
!       x = length (V);
!       xx = ceil (x/2);
!       retval = V([xx+1:x, 1:xx]);
!     elseif (ismatrix (V))
!       nd = ndims (V);
!       sz = size (V);
!       sz2 = ceil (sz ./ 2);
!       cmd =  ["retval = V ([", num2str(sz2(1)+1), ":", num2str(sz(1)), ", 1:", num2str(sz2(1)), "]"];
!       for i=2:nd
!         cmd =  [cmd, ",[", num2str(sz2(i)+1), ":", num2str(sz(i)), ", 1:", num2str(sz2(i)), "]"];
!       endfor
!       cmd = [cmd, ");"];
!       eval (cmd);
!     else
!       error ("fftshift: expecting vector or matrix argument");
!     endif
    endif
  
  endfunction