Improvements to GIZMO implementation
Mixture of small improvements:
- Do not call external functions for min and max.
- Do not use double-precision constants.
- Reduce the number of divisions.
I believe this speeds up the Evrad collapse by 15-20%. @jborrow could you confirm this on your accuracy vs. time plot?
@bvandenbroucke I am likely to have made a mistake somewhere. Could you cross-check that it is all fine?