[gmx-users] double sum over neighbor list

[Sikandar Mashayak]

Hi

I am tyring to compute total virial, i.e. sum_i sum_j (rij*Fij). To achieve
this, I am making modifications in the gmx_nb_generic_kernel() function in
nb_generic.c. In it, I see that atoms I and j are accessed from neighbor
lists to determine forces on atom I . My question is that in this loop do I
have to take care of double counting pair forces, i.e. will the pair of
atom I and j be accessed twice or just once?

Thanks
Sikandar