Is g_hydorder available only in certain versions of GROMACS? I am using version 4.5.3 and it says that g_hydorder is not found. Perhaps it is time to update. Blake -- View this message in context: http://gromacs.5086.x6.nabble.com/order-parameter-tp4455094p5014563.html Sent from the GROMACS Users Forum mailing list archive at Nabble.com.