AMBER Archive (2007)

Subject: Re: AMBER: Is there any way to extract one frame from a whole trajectory just saving one file by using ptraj

From: Gustavo Seabra (gustavo.seabra_at_gmail.com)
Date: Tue May 15 2007 - 14:11:21 CDT

j j wrote:
> Dear amber users,
> I'm using ptraj and I would like to extract a restart file from a
> trajectory.
> I know is the frame 92, so one way is going to the corresponding
> trajectory file of the molecular dynamics by dividing the
> number of frames collected in each trajectory file (20) and giving
> as input just it.
> But for example if I would like to process the whole trajectory
> (Coordinate processing will occur on 441 frames),
> Is there anyway to specify to ptraj that I want just to extract
> the frame 92 after read all the frames without having to save
> anything else?,
> Thank you,
> JJ
>
Have you tried to play with the 'trajin' options? My guess is something like
  
    trajin <file> 92 92 1

should work, if you already *know* that the only one you want is frame
92. (I'm not sure if you would use 92 or 91 there though.)

Gustavo.

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