top::PDFScaleFactorCalculator::PDFSet Node1 top::PDFScaleFactorCalculator ::PDFSet + PDFSet() + PDFSet() Node2 std::vector< float > + elements Node2->Node1 +event_weights +sum_of_event_weights Node3 std::vector< std::unique _ptr< const LHAPDF::PDF > > Node3->Node1 +pdf_members Node4 std::unique_ptr< const LHAPDF::PDF > + ptr + operator->() Node4->Node3 +elements