coul/long and pppm

Dear Lammps Users

I am using coul/long for denoting the interaction between charged particles.

I also want to implement kspace_style pppm to accuracy of 10^-5 for calculation of electrostatic interaction.

What should be the global cut off for coul/long or how it can be determined for use it with kspace_style.

Thanks and Regards

You can use any cutoff you wish. The longer the cutoff, the more work
is done by the pair style. The shorter the cutoff, the more
work is done by the KSpace style. The sum of the pair and KSpace
energy (forces) should be the same independent of the
cutoff (within the accuracy tolerance).

Just try it. Examining the output (timings and grid size and # of neighbors)
will give you a sense of what LAMMPS is doing.