Matrix for double pendulum not populating last column

Hi, I have written this code to solve a double pendulum using ode 45 but the last column isn't populating. Any idea why?

[Zoltán Csáti]

Could you show your paper work? Perhaps you committed a typo.

[Jan]

I've formatted the code.

Answer 1

[Youssef Khmou]

This problem is sensitive to initial conditions, you can start by checking the equations, or values given to variables. In function callpen if for example you change the displacement b to 2.99 instead of 3, the fourth column changes : [0,0.0113,0.0225,0.0338,....,0.6760]