Inti - the cell array jerkdef has the different Jerk* fields for your struct, but you only add these fields on each iteration of the second for loop
for k = 1:size(sensors,2)
for q = 1: length(accdef) % <---- SHOULD THIS BE jerkdef INSTEAD??
for u = 1:nEVENTS/2
% Calculate jerk
JERK(k).event(u).(jerkdef{q}) = diff(Cycle(k).event(u).(accdef{q}));
% Norm of jerk
JERK(k).event(u).NormJerk = ...
sqrt(((JERK(k).event(u).Jerk_X).^2 + (JERK(k).event(u).Jerk_Y).^2 + (JERK(k).event(u).Jerk_Z).^2));
end
end
end
Here is the line that adds the field
JERK(k).event(u).(jerkdef{q}) = diff(Cycle(k).event(u).(accdef{q}));
but this will just add the qth field. When q is 1, then all we have added is the Jerk_X field and so an attempt to calculate something using Jerk_Y and Jerk_Z will fail. You need to add these fields first before you try to access them.
