Expand

psiList = Expand(Psi) expands a state $\Psi$ written as a sum over single Slater determinant states $\psi_i$ into a list of single Slater determinant states $\psi_i$. psiList has $2^{N_F}$ elements.

psiList = Expand(Psi,indexlist) expands only the indices included in index list. psiList has $2^{Len}$ with len=#indexlist elements.