This is a zero-crossing events error. The events locator is incapable of capturing a zero crossing for complex signals.
You can see this by adding the following code to the 'events' subfunction in 'ODE_events_error.m'function:
if ~isreal(state(2))
error('Imaginary Events signal (%g +i%g) at r=%.16f.',real(state(2)),imag(state(2)),r)
end
You will see that during the simulation the value state(2) becomes complex, and the following error message is returned:
??? Error using ==> mycode>events at 37
Imaginary Events signal (4.02767e-009 +i7.46735e-027) at r=2.7392559940601449.
