Find exceeds array ERROR

Hello everybody,

I came across with this error in my code which is below, What should I do to fix it?

Code:

%%  step15: Phase Locking Value (PLV)
% How well waves' phases are locked in a phase synchrony. The main idea is 
% to take the phases of waveforms by taking into account the real part of the Hilbert Transform of signals.
% Then applying the equation.
%Here we take phases for subject one. Variable " phis " is then the phases of 91 signals of subject one.
sujeto = 1;
phis = angle(hilbert(subs_cd1_al(:,:,sujeto)'));
% Now computing PLV over phases "phis" of subject one.
pairs = nchoosek(1:4,1);           % all combinations of 4 channels
plv = zeros(4,4);
for pr = 1 : length(pairs)
    plv(pairs(pr,1), pairs(pr,2)) = abs(sum(exp(1i* ( phis(:,pairs(pr,1)) - phis(:,pairs(pr,2)) ))))/length(phis);
end
plv = plv + plv';                   % we take its transpose to create the connectivity matrix

figure
imagesc(plv);colorbar;
axis square;    colorbar
title('PLV')

Error:

Index in position 2 exceeds array bounds (must not exceed 1).

Error in NEW1 (line 296)
plv(pairs(pr,1), pairs(pr,2)) = abs(sum(exp(1i* ( phis(:,pairs(pr,1)) - phis(:,pairs(pr,2)) ))))/length(phis);

Answer 1

[Les Beckham]

One obvious problem with this code is where you try to access pairs(pr,2) but pairs is a one dimensional (4x1) vector. Perhaps you need to revise the definition of pairs?

pairs = nchoosek(1:4,1)

pairs = 4×1

1 2 3 4

Maybe you meant this?

pairs = nchoosek(1:4,2)

pairs = 6×2

1 2 1 3 1 4 2 3 2 4 3 4