[gmx-users] make_ndx error

[Albert]

Hello:

  I am using make_ndx to make a index file in Gromacs 4.6,

make_ndx -f input.pdb

  but it said:


Copied index group 1 'Protein'
Copied index group 25 'Water_and_ions'
One of your groups is not ascending
Group is empty

thank you very much
best
Albert