Converting basis

[RichRick1]

@gabrielasd @AYSE-GOCER so basically we are working with this and this methods. You can use my garbage-like code
This paper might be helpful

[gabrielasd]

@RichRick1, a few questions:

a) what convention for the ordering of the spin-orbitals are we using? Is it the one documented on these L24-L40 form the older MoHam version?

b) Is the integral parameter in those functions the ones generated by this one_body and two_body methods? Are the integrals built by those last two methods already in the general QC Hamiltonian format (i.e h_pq and g_pqrs?

Another good reference: This notes on symmetry of the integrals from David Sherill's site

[RichRick1]

@gabrielasd
a) yes, we do use notation from the documents in lines L24-L40 (it's also in agreement with the ordering from notes as far as I know)
b) The integral is exactly the output from this generate_one_body and generate_two_body methods. The idea is that the output of these methods is in the sparse format: regular Scipy.sparse.csr_matrix for 1 body integral and dictionary of indices/values of non zero elements for 2 body integral (just keep this in mind cuz regular numpy operations won't work). However, besides the data format, it should be the general QC Hamiltonian format
Hope it helps!

[RichRick1]

1. Every Ham should have 'sym' that is defined when Ham is created.
2. User can change the output file symmetry if symmetry is lower that the initial one
3. Convert to None symmetry before saving to_fcidump