anchor.diff:    double precision               :: phase
     integer                        :: exc(0:2,2,2)
     double precision               :: hij
  -  integer                        :: idx(0:Ndet)
  +  integer,allocatable            :: idx(:)
     
     ASSERT (Nint > 0)
     ASSERT (N_int == Nint)
  
positive.code:   ASSERT (Ndet > 0)
    ASSERT (Ndet_max >= Ndet)
    i_H_psi_array = 0.d0
    call filter_connected_i_H_psi0_SC2(keys,key,Nint,Ndet,idx,idx_repeat)
    do ii=1,idx(0)
      i = idx(ii)
  
negative.code:   double precision               :: phase
    integer                        :: exc(0:2,2,2)
    double precision               :: hij
    integer,allocatable            :: idx(:)
    integer                        :: n_interact
    BEGIN_DOC
    ! <key|H|psi> for the various Nstates
    END_DOC
  