oqp.export.fcidump
==================

.. py:module:: oqp.export.fcidump

.. autoapi-nested-parse::

   .. code-block:: text

      FCIDUMP export for OQP reference orbitals.

      This delegates to the in-tree :mod:`oqp.quantum` package, which builds the
      second-quantized Hamiltonian from OpenQP's *own* AO integrals (``OQP::Hcore``
      and the native two-electron integrals ``OQP::ERI_AO``) in OpenQP's MO basis --
      so the AO ordering/normalization is guaranteed consistent and the file is the
      genuine OpenQP Hamiltonian (no foreign integral engine, nothing silently
      mixed). It does not reimplement the writer.

      :func:`verify_fcidump_fci` is an optional cross-check: read the FCIDUMP, run a
      PySCF FCI, and compare to PySCF's native FCI for the same system (FCI is
      invariant to the orbital choice, so this is a clean ground truth). It honours
      the spin sector (``MS2``) recorded in the file, so open-shell dumps verify
      correctly.



Functions
---------

.. autoapisummary::

   oqp.export.fcidump.dump_fcidump
   oqp.export.fcidump.build_pyscf_mol
   oqp.export.fcidump.verify_fcidump_fci


Module Contents
---------------

.. py:function:: dump_fcidump(path, mol, tol=1e-12)

   .. code-block:: text

      Write a FCIDUMP for the OQP reference MOs via :mod:`oqp.quantum`.

      Returns a small metadata dict (norb / nelec / ms2 / core energy).


.. py:function:: build_pyscf_mol(mol)

   .. code-block:: text

      Construct a PySCF Mole matching the OQP molecule/basis (for the FCI
      cross-check only).


.. py:function:: verify_fcidump_fci(path, mol)

   .. code-block:: text

      Read FCIDUMP -> PySCF FCI, honouring MS2; compare to native PySCF FCI.