init_cc_hash Subroutine

    subroutine init_cc_hash(hash_table, hash_table_size)
        ! routine to setup the hash for the quadrupels
        type(cc_hash), pointer, intent(inout) :: hash_table(:)
        integer, intent(in) :: hash_table_size

        integer :: i
        ! estimate the hash table size with num_doubles^2 for now..
        ! although this number can be reduced substantially i guess

        allocate(hash_table(hash_table_size))

        do i = 1, hash_table_size
            hash_table(i)%found = .false.
            hash_table(i)%amp = 0.0_dp
            nullify (hash_table(i)%next)
        end do

    end subroutine init_cc_hash