function y= spectral_adf(x, varargin)
funcprot(0);
rhs= argn(2);
if(rhs<1 | rhs>3)
error("Wrong number of input arguments")
end
select(rhs)
case 1 then
y= callOctave("spectral_adf", x);
case 2 then
y= callOctave("spectral_adf", x , varargin(1));
case 3 then
y= callOctave("spectral_adf", x , varargin(1), varargin(2));
end
endfunction