Question about SPH cpp

Hi everyone! I’m starting to study the sph method in lammps and have a beginners question: I’m looking at the heat conduction cpp file and the formula is very different from the one that can be derived theoretically (see for example, equation 7.4). Is someone familiar enough with the derivation of the lammps cpp code to explain that to me? I’ve been trying for a while and can’t seem to get the same equation.
Thanks a lot and sorry for the inconvenience!

I suggest you send an email to Georg (CCd) who wrote the USER-SPH package.

See USER-SPH/README for more info.