hello
I tweaked a bit your code , if fact it was simpler in my opinion to do the full 4 x 4 loops instead of doing the specific counter condition
now there is one point that surprises me, its the diagonal of your matrice . the autocorrelation of each element with itself should be 1 and not zero (and it's what I get) - so I wonder about this point. of course we can change the code to force the diagonal to be zero but that sounds strange to me
p = dir('f*.txt');
nFiles = numel(p);
counter=0;
for kk = 1:nFiles
%counter= kk+1
fileID1 = fopen(p(kk).name,'rt');
C_data = textscan(fileID1,'%f');
f1 = cell2mat(C_data); % A = dlmread(p(k).name);
%A_cat{kk} = A; disp(size(A_cat));
fclose(fileID1);
%val = cell(1, nFiles-1); % Memory Pre-allocation
for i = 1: nFiles
fileID2 = fopen(p(i).name,'rt');
C_data = textscan(fileID2,'%f');
f2 = cell2mat(C_data); % A = dlmread(p(k).name);
fclose(fileID2);
[Pyy,freq]=cpsd(f2,f2,hanning(512),[],512,500);
[Pxy,freq]=cpsd(f1,f2,hanning(512),[],512,500);
[Pxx,freq]=cpsd(f1,f1,hanning(512),[],512,500);
coh= (Pxy)./sqrt(Pxx.*Pyy);
val(kk,i)=real(coh(42)) ;
end
end
% gives :
val =
1.0000 0.6725 -0.2602 0.3779
0.6725 1.0000 0.1127 0.2854
-0.2602 0.1127 1.0000 0.0763
0.3779 0.2854 0.0763 1.0000
