Pointcharge support

[RagnarB83]

Hi, very nice project.
I'm developing ASH, a general QM/MM program with interfaces to many programs including pySCF: https://github.com/RagnarB83/ash

In order for gpu4pyscf to be applicable to QM/MM, basic pointcharge support would be required (i.e. for standard electrostatic embedded QM/MM).
As far as I can tell, a compatible pyscf.qmmm.mm_charge function would be needed:
currently we get an assertion error:
assert (isinstance(method, (scf.hf.SCF, mcscf.casci.CASBase)))

Is pointcharge support planned?

[wxj6000]

Thanks. It would be very interesting to see the application of GPU4PySCF in QM/MM. We should be able to complete the module near future.

The assertion error is raised because GPU4PySCF object is different from PySCF object. The PySCF module does not recognize GPU4PySCF object.