Included failsafe and edited break condition

[kyliow]

Hi Steven,

I found out that the 'while' loop new_masses() loops indefinitely if all the previous stars are considered as stars (i.e. if no stars are filtered out in lines 72-80). This scenario unfortunately happens frequently when stellar_mass ~ 10 MSun, and almost definitely happen when stellar_mass is small. I think this is due to two reasons:

1. The break condition in line 84 is wrong. Let previous_number_of_stars = A. For the first 0th, 1st, and 2nd iteration:

N-th interation	previous_number_of_stars	len(additional_mass)	len(mass)	condition
0	A	0	A	A + 0 > A (False)
1	A	n0	A+n0	A + n0 > A + n0 (False)
2	A	n1	A + n0 + n1	A + n1 > A + n0 + n1 (False)

and so on. The condition will never be true for any len(additional_mass) (edit: correct logic). Please correct me if I misunderstood, but I think you probably want len(mass) > number_of_stars, where number_of_stars is the parameter.

2. In almost all scenarios,len(additional_mass) becomes 0 within 2 iterations. A failsafe is needed to break the loop. I set the max count to 10, but this can be added as a parameter (though I doubt it needs changing).

Thanks!