The ratio $v_2\{{\rm 2PC}\}/v_2[{\rm 2PC}]$ in p--Pb collisions at $\snn$ = 5.02 TeV as a function of transverse momentum (red points). Statistical (systematic) uncertainties are represented by solid bars (filled boxes). Calculations from AMPT with string melting and 3DGlauber+MUSIC+UrQMD are shown as textured and plain bands, respectively.