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function c=ref_dftiv(f)
%-*- texinfo -*-
%@deftypefn {Function} ref_dftiv
%@verbatim
%REF_DFT Reference Discrete Fourier Transform Type IV
% Usage: c=ref_dftiv(f);
%
% This is highly experimental!
%@end verbatim
%@strong{Url}: @url{http://ltfat.github.io/doc/reference/ref_dftiv.html}
%@end deftypefn
% Copyright (C) 2005-2016 Peter L. Soendergaard <peter@sonderport.dk>.
% This file is part of LTFAT version 2.2.0
%
% This program 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.
%
% This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
L=size(f,1);
W=size(f,2);
% Create weights.
w=sqrt(1/L);
% Create transform matrix.
F=zeros(L);
for m=0:L-1
for n=0:L-1
F(m+1,n+1)=w*exp(2*pi*i*(m+.5)*(n+.5)/L);
end;
end;
% Compute coefficients.
c=F'*f;
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