For the AlFeFe system, LASSIS reproduces LASSI [1,5] in the (11,10) active space and LASSI [1,21] in the (11,20) active space, despite in both cases building only at most six fragment statelets in any given Hilbert space, as shown in Table . As discussed in Sec. 2.3.2 above, LASSI[r,q] converges more slowly in the larger active space because the minimization of the fragment statelet total energy [Eq. ( )], while completely ignoring the coupling between states [Eq. ( )], tends to bias the algorithm in favor of statelets in which the electron is removed from the closed-shell doubly-occupied 3d orbital, which does not contribute to Table : The magnetic coupling constant predicted by LASSI [1,q], LASSIS, CASCI, LASSIS-PDFT, and CASCI-PDFT for the AlFeFe system in the (11,10) and (11,20) active spaces in cm -1 .