Are there good benchmarks available for testing homemade Ewald summation code?
Optimally it would be very nice if there was several types of systems.
NIST has a very nice benchmark for energies of SPC/E water configurations NIST SPCE made up of 100, 200, 300, 750 water molecules and breaks the energy down into LJ, LJ long range correction, Ewald real, Ewald recipricol, Ewald self, Ewald intra.
However, it would be nice to also test Forces and pressure as well. It would also be nice to do this for flexible molecules.
While it is possible to generate a configuration in an open source package like Gromacs for instance, I am hesitant because there are so many unseen variables. The NIST data is very clear on what their parameters were and it takes no digging to ensure you use the same protocol. It doesn't help that it is well known that different packages, when given the same input parameters return different results, even if slightly different. A simple, purpose made testing code/database would be nice.