is_allowed_double Function

private pure function is_allowed_double(this, exc, supergroup)

Check if a double excitation is allowed.

Is called once at initialization, so it does not have to be super fast. recoupling allows recoupling excitations that change the spin projection of individual GAS spaces.

Type Bound



Type IntentOptional Attributes Name
class(GASSpec_t), intent(in) :: this
type(Excite_2_t), intent(in) :: exc
integer, intent(in) :: supergroup(:)

Return Value logical