[gmx-users] trjconv -drop options

[Gregory Man Kai Poon]

Hi all:

I am trying to use the gmx trjconv -drop options to pull frames 
according to criteria in the Y column of an .xvg output (e.g., 
rmsd.xvg), and I am unable to find documentation beyond the command 
reference.  It sounds like one specifies the file with -drop and and 
then use -dropover and -dropunder to specify a range, presumably in the 
Y value, but it does not actually say.  I am unable to figure out what 
the mechanics of these parameters are, as trial values based on the 
sample Y columns produce unexpected selection of frames.  If anyone can 
share their experience, that would be great.

Many thanks,

Gregory