[gmx-users] number of frames in trajectory

[Erik Lindahl]

Hi David,

There's no way of doing that without reading to the end - when we write  
the first frame we don't know if the simulation will be stopped with a  
signal or crash for some reason. The user might also have concatenated  
trajectories from several runs, so don't trust the tpr file either...


Theoretically you could imagine back and setting the number of frames  
in a header when the simulation is finished, but that type of random  
file access wouldn't work on a lot of filesystems.

Cheers,

Erik


On Jun 29, 2004, at 5:36 PM, David L. Bostick wrote:

>
> Dear all,
>
> I am writing an analysis code, and I want to know the best way to get  
> the
> number of frames contained in a trajectory file ... preferably w/o  
> reading
> all the frames.  I saw in statutil.h the nframes_read() function, but  
> I'm
> not sure if this is what I need.
>
> Thanks,
> David
>
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