Calculation Question about Rank

[ZMC12342]

Hello and thank you for your outstanding work. I would like to ask why the rank values are calculated in this way, and does the expression ensure that the rank values are different for point clouds from different BEV grids?

lift-splat-shoot/src/models.py

Line 222 in d74598c

ranks = geom_feats[:, 0] * (self.nx[1] * self.nx[2] * B)\