function [S,f,Serr]=mtspectrumc(data,params)
% Multi-taper spectrum - continuous process
% 
%  Usage:
% 
%  [S,f,Serr]=mtspectrumc(data,params)
%  Input: 
%  Note units have to be consistent. See chronux.m for more information.
%        data (in form samples x channels/trials) -- required
%        params: structure with fields tapers, pad, Fs, fpass, err, trialave
%        -optional
%            tapers : precalculated tapers from dpss or in the one of the following
%                     forms: 
%                     (1) A numeric vector [TW K] where TW is the
%                         time-bandwidth product and K is the number of
%                         tapers to be used (less than or equal to
%                         2TW-1). 
%                     (2) A numeric vector [W T p] where W is the
%                         bandwidth, T is the duration of the data and p 
%                         is an integer such that 2TW-p tapers are used. In
%                         this form there is no default i.e. to specify
%                         the bandwidth, you have to specify T and p as
%                         well. Note that the units of W and T have to be
%                         consistent: if W is in Hz, T must be in seconds
%                         and vice versa. Note that these units must also
%                         be consistent with the units of params.Fs: W can
%                         be in Hz if and only if params.Fs is in Hz.
%                         The default is to use form 1 with TW=3 and K=5
% 
%             pad            (padding factor for the FFT) - optional (can take values -1,0,1,2...). 
%                     -1 corresponds to no padding, 0 corresponds to padding
%                     to the next highest power of 2 etc.
%                        e.g. For N = 500, if PAD = -1, we do not pad; if PAD = 0, we pad the FFT
%                        to 512 points, if pad=1, we pad to 1024 points etc.
%                        Defaults to 0.
%            Fs   (sampling frequency) - optional. Default 1.
%            fpass    (frequency band to be used in the calculation in the form
%                                    [fmin fmax])- optional. 
%                                    Default all frequencies between 0 and Fs/2
%            err  (error calculation [1 p] - Theoretical error bars; [2 p] - Jackknife error bars
%                                    [0 p] or 0 - no error bars) - optional. Default 0.
%            trialave (average over trials/channels when 1, don't average when 0) - optional. Default 0
%  Output:
%        S       (spectrum in form frequency x channels/trials if trialave=0; 
%                in the form frequency if trialave=1)
%        f       (frequencies)
%        Serr    (error bars) only for err(1)>=1


 if nargin < 1; error('Need data'); end;
 if nargin < 2; params=[]; end;
 [tapers,pad,Fs,fpass,err,trialave,params]=getparams(params);
 if nargout > 2 && err(1)==0; 
 %   Cannot compute error bars with err(1)=0. Change params and run again.
     error('When Serr is desired, err(1) has to be non-zero.');
 end;
 data=change_row_to_column(data);
 N=size(data,1);
 nfft=max(2^(nextpow2(N)+pad),N);
 [f,findx]=getfgrid(Fs,nfft,fpass); 
 tapers=dpsschk(tapers,N,Fs); % check tapers
 J=mtfftc(data,tapers,nfft,Fs);
 J=J(findx,:,:);
 S=squeeze(mean(conj(J).*J,2));
 if trialave; S=squeeze(mean(S,2));end;
 if nargout==3; 
    Serr=specerr(S,J,err,trialave);
 end;