Changed f_ij factors in SPHENIX to respect unequal m
The default f_ij
factors in SPHENIX do not actually square with what they should be.
This is because we do not use the density for determining the number of neighbours, but rather the number density. This means that in ye-olde-Hopkins parlance, we have \tilde{x} = 1
and x = m
.
This is a minor change that has little effect anywhere, but I would rather have it right than not.