function x = hilbert(xr,n)

if nargin<2, n=[]; end
if ~isreal(xr)
  warning('HILBERT ignores imaginary part of input.')
  xr = real(xr);
end

[xr,nshifts] = shiftdim(xr);
if isempty(n)
  n = size(xr,1);
end
x = fft(xr,n,1); 
h  = zeros(n,~isempty(x));
if n>0 & 2*fix(n/2)==n

  h([1 n/2+1]) = 1;
  h(2:n/2) = 2;
elseif n>0

  h(1) = 1;
  h(2:(n+1)/2) = 2;
end
x = ifft(x.*h(:,ones(1,size(x,2))));

x = shiftdim(x,-nshifts);