  The localized active space self consistent field (LASSCF) method factorizes a
complete active space (CAS) wave function into an antisymmetrized product of
localized active space wave function fragments. Correlation between fragments
is then reintroduced through LAS state interaction (LASSI), in which the
Hamiltonian is diagonalized in a model space of LAS states. However, the
optimal procedure for defining the LAS fragments and LASSI model space is
unknown. We here present an automated framework to explore systematically
convergent sets of model spaces, which we call LASSI[$r$,$q$]. This method
requires the user to select only $r$, the number of electron hops from one
fragment to another and $q$, the number of fragment basis functions per Hilbert
space, which converges to CASCI in the limit of $r,q\to\infty$. Numerical tests
of this method on the tri-metal complexes
[Fe(III)Al(III)Fe(II)($\mu_3$-O)]$^{6+}$ and
[Fe(III)$_2$Fe(II)($\mu_3$-O)]$^{6+}$ show efficient convergence to the CASCI
limit with 4-10 orders of magnitude fewer states.
