Duplicity in RHS_Struct

Hi!

I am using the SINDy-PI with the example of SinglePendulumOnChart and, when I change the LibPoly and GuessPoly from its initial definition to _LibPoly=[2;1;0;0];_ and _GuessPoly=[2;1;0;0];_ I observe that the RHS_Struct has repeated terms, i.e., all the combinations between the states appear twice. I don't know if it is a bug or if it is necessary in order to discover the model.