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function gf=filterbankresponse(g,a,L,varargin)
%FILTERBANKRESPONSE Response of filterbank as function of frequency
% Usage: gf=filterbankresponse(g,a,L);
%
% `filterbankresponse(g,a,L)` computes the total response in frequency of
% a filterbank specified by *g* and *a* for a signal length of
% *L*. This corresponds to summing up all channels. The output is a
% usefull tool to investigate the behaviour of the windows, as peaks
% indicate that a frequency is overrepresented in the filterbank, while
% a dip indicates that it is not well represented.
%
% In mathematical terms, this function computes the diagonal of the
% Fourier transform of the frame operator when the filterbank is painless.
%
% `filterbankresponse(g,a,L,'real')` does the same for a filterbank
% intended for positive-only filterbank.
%
% `filterbankresponse(g,a,L,fs)` specifies the sampling rate *fs*. This
% is only used for plotting purposes.
%
% `filterbankresponse` takes the following optional parameters:
%
% 'fs',fs Sampling rate, used only for plotting.
%
% 'complex' Assume that the filters cover the entire frequency
% range. This is the default.
%
% 'real' Assume that the filters only cover the positive
% frequencies (and is intended to work with real-valued
% signals only).
%
% 'noplot' Don't plot the response, just return it.
%
% 'plot' Plot the response using |plotfftreal|.
%
% See also: filterbank, filterbankbounds
definput.flags.ctype={'complex','real'};
definput.flags.plottype={'noplot','plot'};
definput.flags.type={'total','individual'};
definput.keyvals.fs=[];
[flags,kv,fs]=ltfatarghelper({'fs'},definput,varargin);
[g,info]=filterbankwin(g,a,L,'normal');
M=info.M;
gf = zeros(L,M);
for m=1:M
gf(:,m) = comp_filterbankresponse(g(m),info.a(m),L,flags.do_real);
end
if flags.do_total
gf = sum(gf,2);
end
if flags.do_plot
if flags.do_real
plotfftreal(gf(1:floor(L/2)+1),fs,'lin');
else
plotfft(gf,fs,'lin');
end;
end;

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