% -*- texinfo -*-
% @deftypefn {Function File} {@var{d} = } gdftmtx (@var{a})
%
% Form a matrix, that can be used to perform Fourier transforms in
% a Galois Field.
%
% Given that @var{a} is an element of the Galois Field GF(2^m), and
% that the minimum value for @var{k} for which @code{@var{a} ^ @var{k}}
% is equal to one is @code{2^m - 1}, then this function produces a
% @var{k}-by-@var{k} matrix representing the discrete Fourier transform
% over a Galois Field with respect to @var{a}. The Fourier transform of
% a column vector is then given by @code{gdftmtx(@var{a}) * @var{x}}.
%
% The inverse Fourier transform is given by @code{gdftmtx(1/@var{a})}
% @end deftypefn
% @seealso{dftmtx}