function [Sc,Cmat,Ctot,Cvec,Cent,f]=CrossSpecMatc(data,win,params) % Multi-taper cross-spectral matrix - another routine, allows for multiple trials and channels % Does not do confidence intervals. Also this routine always averages over trials - continuous process % % Usage: % % [Sc,Cmat,Ctot,Cvec,Cent,f]=CrossSpecMatc(data,win,params) % Input: % Note units have to be consistent. See chronux.m for more information. % data (in form samples x channels x trials) % win (duration of non-overlapping window) % params: structure with fields tapers, pad, Fs, fpass % - 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. Defaults to 0. % e.g. For N = 500, if PAD = 0, we pad the FFT % to 512 points; if PAD = 2, we pad the FFT % to 2048 points, etc. % 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 % Output: % Sc (cross spectral matrix frequency x channels x channels) % Cmat Coherence matrix frequency x channels x channels % Ctot Total coherence: SV(1)^2/sum(SV^2) (frequency) % Cvec leading Eigenvector (frequency x channels) % Cent A different measure of total coherence: GM/AM of SV^2s % f (frequencies) d=ndims(data); if d<2, error('Need multidimensional array'); end if d==2, [N,C]=size(data); end; if d==3, [N,C,Ntr]=size(data); end; if nargin < 3; params=[]; end; [tapers,pad,Fs,fpass,err,trialave,params]=getparams(params); clear err trialave params nwin=round(win*Fs); nfft=max(2^(nextpow2(nwin)+pad),nwin); [f,findx]=getfgrid(Fs,nfft,fpass); tapers=dpsschk(tapers,nwin,Fs); % check tapers Sc=zeros(length(findx),C,C); Nwins=floor(N/nwin); if d==3, % If there are multiple trials for iwin=1:Nwins, for i=1:Ntr, data1=squeeze(data(1+(iwin-1)*nwin:iwin*nwin,:,i)); J1=mtfftc(detrend(data1),tapers,nfft,Fs); J1=J1(findx,:,:); for k=1:C, for l=1:C, spec=squeeze(mean(conj(J1(:,:,k)).*J1(:,:,l),2)); Sc(:,k,l)=Sc(:,k,l)+spec; end end end end Sc=Sc/(Nwins*Ntr); end if d==2, % only one trial for iwin=1:Nwins, data1=squeeze(data(1+(iwin-1)*nwin:iwin*nwin,:)); J1=mtfftc(data1,tapers,nfft,Fs); J1=J1(findx,:,:); for k=1:C, for l=1:C, Sc(:,k,l)=Sc(:,k,l)+squeeze(mean(conj(J1(:,:,k)).*J1(:,:,l),2)); end end end Sc=Sc/Nwins; end Cmat=Sc; Sdiag=zeros(length(findx),C); for k=1:C, Sdiag(:,k)=squeeze(Sc(:,k,k)); end for k=1:C, for l=1:C, Cmat(:,k,l)=Sc(:,k,l)./sqrt(abs(Sdiag(:,k).*Sdiag(:,l))); end end Ctot=zeros(length(findx),1); Cent=Ctot; Cvec=zeros(length(findx),C); for i=1:length(findx), [u s]=svd(squeeze(Sc(i,:,:)));s=diag(s); Ctot(i)=s(1)/sum(s); Cent(i)=exp(mean(log(s)))/mean(s); Cvec(i,:)=transpose(u(:,1)); end