Questions about Ewald summation

[ley61]

Hi~ there, I went through pyqmc code these days and quite enjoy it. But I have a question then about the Ewald summation class.

It's mentioned in pyqmc document that real-space interaction between electron and its own images is ignored. The same strategy is also applied to ions.

I get quite confused since it seems we should include these image interactions in energy calculation. Does this mean we can actually ignore image interactions in calculations, or this neglection is justified only on some occasions?

I have check these image terms in NaCl case and they are actually quite small, but I'm still worried about more generally cases.

[lkwagner]

I believe this is just a constant offset to the energy, so it doesn't affect any physics. Most codes drop it, so for compatibility we do as well.

[ley61]

OK, thanks for the reply~