[gmx-users] g_sgangle problem

[yousef nademi]

hi gromacs users and especially Dr. Justine
in using the g_sgangle i have to define index file contain multiple of two defining all the P and N atoms but after executing the g_sgangle i get the message:something wrong with contents of index file
after defining the one p atom and 1 n atom then there was no problem
should i define all the index file to 2 group part and then average from the rezult
or should i do something in index file that can solve the problem
best regards
yousef nademi