Home > chronux_1_50 > pointbinned > mtspectrumsegpb.m

mtspectrumsegpb

PURPOSE ^

Multi-taper segmented spectrum for a univariate binned point process

SYNOPSIS ^

function [S,f,R,varS,zerosp,C,Serr]=mtspectrumsegpb(data,win,params,segave,fscorr)

DESCRIPTION ^

 Multi-taper segmented spectrum for a univariate binned point process

 Usage:

 [S,f,R,varS,zerosp,C,Serr]=mtspectrumsegpb(data,win,params,segave,fscorr)
 Input: 
 Note units have to be consistent. See chronux.m for more information.
       data (single vector) -- required
       win  (duration of the segments) - required. 
       params: structure with fields tapers, pad, Fs, fpass, err
       - optional
           tapers (precalculated tapers from dpss, or in the form [NW K] e.g [3 5]) -- optional. If not 
                                                 specified, use [NW K]=[3 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.
       segave (1 for averaging across segments, 0 otherwise; default 1)
       fscorr   (finite size corrections, 0 (don't use finite size corrections) or 1 (use finite size corrections) - optional
                (available only for spikes). Defaults 0.
 Output:
       S       (spectrum in form frequency x segments if segave=0; as a function of frequency if segave=1)
       f       (frequencies)
       R       (spike rate)
       varS    (variance of the log spectrum)
       zerosp  (0 for segments in which spikes were found, 1 for segments
       in which there are no spikes)
       C       (covariance matrix of the log spectrum - frequency x
       frequency matrix)
       Serr    (error bars) - only for err(1)>=1

CROSS-REFERENCE INFORMATION ^

This function calls: This function is called by:

SOURCE CODE ^

0001 function [S,f,R,varS,zerosp,C,Serr]=mtspectrumsegpb(data,win,params,segave,fscorr)
0002 % Multi-taper segmented spectrum for a univariate binned point process
0003 %
0004 % Usage:
0005 %
0006 % [S,f,R,varS,zerosp,C,Serr]=mtspectrumsegpb(data,win,params,segave,fscorr)
0007 % Input:
0008 % Note units have to be consistent. See chronux.m for more information.
0009 %       data (single vector) -- required
0010 %       win  (duration of the segments) - required.
0011 %       params: structure with fields tapers, pad, Fs, fpass, err
0012 %       - optional
0013 %           tapers (precalculated tapers from dpss, or in the form [NW K] e.g [3 5]) -- optional. If not
0014 %                                                 specified, use [NW K]=[3 5]
0015 %            pad            (padding factor for the FFT) - optional (can take values -1,0,1,2...).
0016 %                    -1 corresponds to no padding, 0 corresponds to padding
0017 %                    to the next highest power of 2 etc.
0018 %                       e.g. For N = 500, if PAD = -1, we do not pad; if PAD = 0, we pad the FFT
0019 %                       to 512 points, if pad=1, we pad to 1024 points etc.
0020 %                       Defaults to 0.
0021 %           Fs   (sampling frequency) - optional. Default 1.
0022 %           fpass    (frequency band to be used in the calculation in the form
0023 %                                   [fmin fmax])- optional.
0024 %                                   Default all frequencies between 0 and Fs/2
0025 %           err  (error calculation [1 p] - Theoretical error bars; [2 p] - Jackknife error bars
0026 %                                   [0 p] or 0 - no error bars) - optional. Default 0.
0027 %       segave (1 for averaging across segments, 0 otherwise; default 1)
0028 %       fscorr   (finite size corrections, 0 (don't use finite size corrections) or 1 (use finite size corrections) - optional
0029 %                (available only for spikes). Defaults 0.
0030 % Output:
0031 %       S       (spectrum in form frequency x segments if segave=0; as a function of frequency if segave=1)
0032 %       f       (frequencies)
0033 %       R       (spike rate)
0034 %       varS    (variance of the log spectrum)
0035 %       zerosp  (0 for segments in which spikes were found, 1 for segments
0036 %       in which there are no spikes)
0037 %       C       (covariance matrix of the log spectrum - frequency x
0038 %       frequency matrix)
0039 %       Serr    (error bars) - only for err(1)>=1
0040 
0041 
0042 if nargin < 2; error('Need data and segment information'); end;
0043 if nargin < 3; params=[]; end;
0044 if nargin < 4 || isempty(segave); segave=1; end;
0045 [tapers,pad,Fs,fpass,err,trialave,params]=getparams(params);
0046 clear params trialave
0047 if nargin < 3 || isempty(fscorr); fscorr=0;end;
0048 
0049 if nargout > 4 && err(1)==0; 
0050 %   Cannot compute error bars with err(1)=0. Need to change params and run again.
0051     error('When Serr is desired, err(1) has to be non-zero.');
0052 end;
0053 data=change_row_to_column(data);
0054 N=size(data,1); % total length of data
0055 dt=1/Fs; % sampling interval
0056 T=N*dt; % length of data in seconds
0057 E=0:win:T-win; % fictitious event triggers
0058 win=[0 win]; % use window length to define left and right limits of windows around triggers
0059 data=createdatamatpb(data,E,Fs,win);
0060 N=size(data,1); % length of segmented data
0061 nfft=max(2^(nextpow2(N)+pad),N);
0062 [f,findx]=getfgrid(Fs,nfft,fpass); 
0063 tapers=dpsschk(tapers,N,Fs); % check tapers
0064 [J,Msp,Nsp]=mtfftpb(data,tapers,nfft);  
0065 J=J(findx,:,:);
0066 R=Msp*Fs;
0067 S=squeeze(mean(conj(J).*J,2)); % spectra of non-overlapping segments (averaged over tapers)
0068 if segave==1; SS=squeeze(mean(S,2));R=mean(R);else;SS=S;end;% mean of the spectrum averaged across segments
0069 if nargout > 3
0070     lS=log(SS); % log spectrum for nonoverlapping segments
0071 %     varS=var(lS,1,2); % variance of log spectrum
0072     varS=var(lS',1)';% variance of the log spectrum R13
0073     if nargout > 4
0074        zerosp=zeros(1,size(data,2));
0075        zerosp(Nsp==0)=1;
0076        if nargout > 5
0077           C=cov(lS'); % covariance matrix of the log spectrum
0078           if nargout==7; 
0079              if fscorr==1;
0080                 Serr=specerr(SS,J,err,segave,Nsp);
0081              else
0082                 Serr=specerr(SS,J,err,segave);
0083              end;
0084           end;
0085        end;
0086     end;
0087 end;
0088 S=SS;

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