How to know the number of frame ?

[li tao]

Dear marioe,

   I want to know how to get the total number of frames of my trajectory file? I run the MD simulation with of total 100 ns in 50000000 steps. Besides, I want to know if I need to the the trajectory file in the last few ns when calculating the alanine scanning free energy? 

    Thanks a lot 

   Tao Li 

[marioe911116]

An easy way to get the number of frames is by using gmx check:

gmx check -f your_traj.xtc

It is recommendable to use the frames where the energy of the system has converged... You can discard a certain number of frames at the beginning of the trajectory... For example, use only the last 10 ns of a 20 ns trajectory...