checkValidSpawnedList Function

    function checkValidSpawnedList(proc) result(list_full)
        ! Check that the position described by ValidSpawnedList is acceptable.
        ! If we have filled up the memory that would be acceptable, then
        ! end the calculation, i.e. throw an error
        logical :: list_full
        integer, intent(in) :: proc
        logical, save :: new_warning = .true.
        list_full = .false.
        if (proc == nNodes - 1) then
            list_full = ValidSpawnedList(proc) > MaxSpawned
        else
            list_full = ValidSpawnedList(proc) >= InitialSpawnedSlots(proc + 1)
        end if
        if (list_full .and. new_warning) then
            ! Only ever print this warning once
            new_warning = .false.
            write(stderr, *) "Attempting to spawn particle onto processor: ", proc
            write(stderr, *) "No memory slots available for this spawn."
            write(stderr, *) "Please increase MEMORYFACSPAWN"
            write(stderr, *) ValidSpawnedList
            write(stderr, *) InitialSpawnedSlots
            ! give a note on the counter-intuitive scaling behaviour
            if (MaxSpawned / nProcessors < 0.1_dp * TotWalkers) then
                write(stderr, *) "Memory available for spawns is too low, number of processes might be too high for the given walker number"
            end if
        end if

    end function checkValidSpawnedList