The transition between regular and Mach reflection for a planar shock reflection from a wedge is investigated numerically by using computational fluid dynamics code for perfect gases without viscosity and heat conduction. The predicted transitions are compared to theoretical transition criteria and other experimental data. The predicted transitions are close to the theoretical criteria and show no significant persistence of regular reflection in the absence of viscosity and heat conduction. This result supports the experimental result by F. J. Barbosa & B. W. Skews.