init_sites_star Subroutine

    subroutine init_sites_star(this)
        ! create the lattice structure of the star geometry..
        ! with one special pivot site with index 1, which is connected
        ! to all the other sites and the other sites are just connected to
        ! the pivot site!
        class(star) :: this
        character(*), parameter :: this_routine = "init_sites_star"

        integer :: i

        if (this%get_nsites() <= 0) then
            call stop_all(this_routine, &
                          "something went wrong: negative or 0 number of sites!")
        else if (this%get_nsites() == 1) then
            this%sites(1) = site(ind=1, n_neighbors=0, neighbors=[integer ::])

        else
            ! first to the special pivot site in the middle of the star
            this%sites(1) = site(ind=1, n_neighbors=this%get_nconnect_max(), &
                                 neighbors=[(i, i=2, this%get_nsites())])

            ! and all the others are just connected to the pivot
            do i = 2, this%get_nsites()
                this%sites(i) = site(ind=i, n_neighbors=1, neighbors=[1])
            end do
        end if

    end subroutine init_sites_star