Maximum difference of internal DOF per vertex between ensemble averaged PG and VPG versus heterogeneity index. The data is collected for different combinations of q
fix and q
fluct. Panels (a) and (b) correspond, respectively, to 3D and 2D lattices with L = 20. Panels (c) and (d) show errors that are much smaller between the VPG and the bar-PG. In addition, in panel (a) shows in green symbols the results obtained for 4 different proteins as explained in the text.