function h=expwave(L,m,cent);
%EXPWAVE Complex exponential wave
% Usage: h=expwave(L,m);
% h=expwave(L,m,cent);
%
% EXPWAVE(L,m) returns an exponential wave revolving m times around the
% origin. The collection of all waves with wave number m=0,...,L-1
% forms the basis of the discrete Fourier transform.
%
% The wave has absolute value 1 everywhere. To get an exponential wave
% with unit l^2-norm, divide the wave by sqrt(L). This is the
% normalization used in the DFT function.
%
% EXPWAVE(L,m,cent) makes it possible to shift the sampling points by
% the amount cent. Default is cent=0.
%
% See also: dft, pchirp
%
% Url: http://ltfat.github.io/doc/fourier/expwave.html
% Copyright (C) 2005-2023 Peter L. Soendergaard <peter@sonderport.dk> and others.
% This file is part of LTFAT version 2.6.0
%
% 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/>.
% AUTHOR : Peter L. Søndergaard
% TESTING: OK
% REFERENCE: OK
complainif_argnonotinrange(nargin,2,3,mfilename);
if nargin==2
cent=0;
end;
h = exp(2*pi*i*((0:L-1)+cent)/L*m).';