% creates the fourieroperator W = exp(j2pi|f><t|)
%
% visualization of the continuous W
% math image_inagtion
%
% use:  W = fourieroperator(200);  % returns the 200 by 200 operator
%       W = fourieroperator(M,N);  % returns the  M  by  N  operator
%       W = fourieroperator(512,512,.4) % scales down freq. range
%                                         (to about same as 200 by 200)
%       W = fourieroperator(M,N,frac); % frac=1 (default): fracfreq -1/2 to 1/2
%
%       note that 400 by 400 too big for qms colorscript
%                            ``copy file is too large''       ... use -s
%
% see also /mas/vision/bigu/steve/matdat/fourierop2dat.m
% fourierop2dat.m creates a datfile with color fourieroperator

function W = dummy(M,N,frac);

if nargin<2
  N = M;
end%if

if nargin<3
  frac = 1;   % default is -1/2 to 1/2 fracfreqlim
end%if

%%t = (0:N-1)/N;  % time span is like 1 second:  [0,1) second
t = linspace(-1/2,1/2,N);  % time span is like 1 second:  [0,1) second
f = linspace(-M/2*frac,M/2*frac,M);   % count by ones, nyquist at M/2 Hertz
                                  % or M/2 cycles in M pts
disp(sprintf('freq. goes from %g to %g cycles (per 1sec total)', -M/2*frac, M/2*frac))
TF = f(:)*t(:).'; % the outer product |f><t|
W  = exp(j*2*pi*TF);
%%%Wr = bordern(real(W)).';
%%%Wi = bordern(imag(W)).';
%%%save deletemer Wr
%%%!mat2ras deletemer.mat fourieroperatorr.ras
%%%save deletemei Wi
%%%!mat2ras deletemei.mat fourieroperatori.ras

