MuonR4::MdtSegmentFitter::ResidualWithPartials Node1 MuonR4::MdtSegmentFitter ::ResidualWithPartials + evalPhiPars + residual + nPars Node2 std::array< Amg::Vector3 D, sumUp(nPars)> Node2->Node1 +hessian Node3 Vector3D Node3->Node2 +elements Node4 std::array< Amg::Vector3 D, nPars > Node3->Node4 +elements Node4->Node1 +gradient