[gmx-users] binding energy calculation when appear this error: no distance restraints in topology

[fatemeh ramezani]

 Dear Justin 
I thought by use of  -pairs I can calculate energy between any 2 groups from index file. when I use g_energy, result is a .xvg file that shows energy of system but I need to calculate energy between specific groups. is there any way for me?   
thanks

Fatemeh Ramezani