Fix FCI RDM tensor contraction in test_accessing_rdm

[anishbhujbal7]

Description

Fixes #52.

This PR resolves an energy mismatch assertion error in test_accessing_rdm() when verifying Full Configuration Interaction (FCI) Reduced Density Matrices (RDMs).

Root Cause

molecule.fci_one_rdm and molecule.fci_two_rdm in PyscfMolecularData return spatial-orbital RDMs matching the spatial convention used by cisd and ccsd RDMs. Previous test variations incorrectly treated these as spin-orbital tensors or applied incorrect cross-spin slicing, leading to tensor dimension mismatches or undercounted two-electron energy contributions.

Changes Made

• Updated test_accessing_rdm() in openfermionpyscf/tests/_pyscf_molecular_data_test.py to contract spatial 1- and 2-body integrals ($h_1, h_2$) directly with molecule.fci_one_rdm and molecule.fci_two_rdm.
• Ensured total calculated energy $E_{\text{tot}}$ matches the PySCF FCI ground-state reference energy $E_{\text{ref}}$ down to machine precision.

Verification

Ran full test suite using PyTest in WSL environment:

./venv_wsl/bin/pytest

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[mhucka]

@anishbhujbal7 Thank you for this work. I have a question about the files. The GitHub diff shows that every line of the file plotter.py has changed. What is going on there?

[anishbhujbal7]

Hi @mhucka, thanks for pointing that out!

That full-file diff was just an accidental line-ending conversion (CRLF vs. LF) when I opened the file in my local Windows/WSL setup.

I've restored examples/plotter.py back to its original state and force-pushed an update. The PR diff should now cleanly show only the test fix in _pyscf_molecular_data_test.py.