Home > eeg > egis > net_utils > eeg_factor.m

eeg_factor

PURPOSE ^

SYNOPSIS ^

function [factor_mag, factor_ph, factor_eig] = eeg_factor(avgcsdm,good_chan,freq,output);

DESCRIPTION ^

CROSS-REFERENCE INFORMATION ^

This function calls: This function is called by:

SOURCE CODE ^

0001 function [factor_mag, factor_ph, factor_eig] = eeg_factor(avgcsdm,good_chan,freq,output);
0002 ch_pair_indices    
0003 if size(avgcsdm,2) == 8385
0004     NChan = 129;
0005 else
0006     error('number of channels is unknown');
0007 end;
0008 
0009 if any(good_chan) > 129
0010     error('channel out of range');
0011 end;
0012 
0013 if freq > size(avgcsdm,1)
0014     error('frequency out of range');
0015 end;
0016 csdm_data = avgcsdm;
0017 csdm_mat = zeros(NChan,NChan);
0018 csdm = zeros(size(good_chan,2),size(good_chan,2));
0019 for ichan =1:NChan
0020     for jchan = ichan:NChan;
0021         csdm_mat(ichan,jchan) = csdm_data(freq,chpair(ichan,jchan));
0022         csdm_mat(jchan,ichan) = conj(csdm_mat(ichan,jchan));
0023     end;    
0024 end;
0025     
0026 csdm = csdm_mat(good_chan,good_chan);
0027 
0028 [vec_csd, val_csd] = eig(csdm,'nobalance');
0029 val_csd = real(val_csd);
0030 factor_eig = diag(val_csd);
0031 vec_csd = vec_csd';
0032 factor_mag = zeros(size(vec_csd,1),129);
0033 factor_mag(:,good_chan) = abs(vec_csd);
0034 phase_data = vec_csd;
0035 if output == 'cos'
0036      phase_data = real(phase_data)./abs(phase_data);
0037 else
0038                                 real_sign = sign(real(phase_data));
0039                                 phase_data = angle(phase_data);
0040                                 ang_sign = sign(phase_data);
0041                                 for iph = 1:size(phase_data,1)
0042                                         for jph = size(phase_data,2)
0043                                                 if real_sign(iph,jph) < 0
0044                                                         phase_data(iph,jph) = phase_data(iph,jph) + pi*real_sign(iph,jph)*ang_sign(iph,jph);
0045                                                 end;
0046                                         end;
0047                                 end;
0048 
0049 
0050                               
0051 end
0052             phase_data(find(isnan(phase_data))) = zeros(size(find(isnan(phase_data))));
0053 
0054             if ~isreal(phase_data)
0055                           error('Phase matrix is not real')
0056                     end
0057 
0058 factor_ph = zeros(size(phase_data,1),129);
0059 factor_ph(:,good_chan) = phase_data;
0060 
0061 
0062

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