quemb.molbe.sparse_2el_integral.get_dense_integrals

quemb.molbe.sparse_2el_integral.get_dense_integrals(ints_3c2e, df_coef)

Compute dense ERIs from sparse 3-center integrals and sparse DF coefficients.

We evaluate the integrals via

\[(\mu, \nu | \rho \sigma) = \sum_{P} (\mu \nu | P) C^{P}_{\rho\sigma}\]

Parameters:

• ints_3c2e (SemiSparseSym3DTensor) – Sparse 3-center integrals in the form of a SemiSparseSym3DTensor. \((\mu \nu | P)\) is given by ints_3c2e[mu, nu][P].

• df_coef (SemiSparseSym3DTensor) – DF coefficients in the form of a SemiSparseSym3DTensor. \(C^{P}_{\mu\nu}\) is given by df_coef[mu, nu][P].

Return type:

ndarray[tuple[int, ...], dtype[float64]]