Basic notions of simulation: investigating the effect of the different mathematical integrators. Press the following keys to activate/deactivate the different pendulums:
"a/A" -> Euler "s/S" -> Semi-Implicit Euler "d/D" -> Heun "f/F" -> Runge-Kutta 2 "x/X" -> Runge-Kutta 4
The difference between the last four methods is barely visible. The computational cost of the Semi-Implicit Euler is the lowest of the four, that's why it is one of the most used integrators.