forte2.dsrg.utils#

Module Contents#

forte2.dsrg.utils.compute_t1_block#
forte2.dsrg.utils.compute_t2_block#
forte2.dsrg.utils.renormalize_V_block#
forte2.dsrg.utils.renormalize_3index#
forte2.dsrg.utils.antisymmetrize_2body(T, indices)#
forte2.dsrg.utils.cas_energy_given_RDMs(E_core, H_cas, V_cas, gamma1, gamma2)#

Return the CAS energy.

\[E_{\mathrm{CAS}} = E_{\mathrm{core}} + \sum_{uv} \langle u | \hat{h} | v \rangle \gamma_v^u + \frac{1}{2} \sum_{uvxy} \langle uv | \hat{g} | xy \rangle \gamma_{xy}^{uv}\]
Parameters:
E_corefloat

The core energy.

H_casnp.ndarray

The one-electron integrals in the CAS.

V_casnp.ndarray

The two-electron integrals in the CAS (not antisymmetrized).

gamma1np.ndarray

The 1-RDM of the CAS reference.

gamma2np.ndarray

The 2-RDM of the CAS reference.

Returns:
float

The CAS energy.