double free or corruption (!prev)

[krzysztofarendt]

> python examples/ray_2_boxes_example.py 

Simulation loop started
Collecting polygon points and faces from the array format
Making the voxel grid
X limits: 0.0 2.0
Y limits: 0.0 1.0
Z limits: 0.0 1.0
double free or corruption (!prev)
Aborted (core dumped)

Possibly related: https://stackoverflow.com/questions/60207653/numba-double-free-or-corruption-prev-aborted-core-dumped

The problem is that list.append method is not thread safe. If you comment out that line, you wont get the error Admittedly Numba documentation can be sparse. But it does mention that when using prange, it's up to the user to ensure there are no "cross iteration dependencies" link

[krzysztofarendt]

This bug happens only from time to time. I believe it is because I'm using prange() and multiple threads sometimes try to write to the same element of the hits array (hits[sn] += energy[rn]).

Fixed in 09ae2faecdead74e130b4dfaefab634146fa3b1d