i need to Counting the number of atoms that passing through a point

how can i do this



06.04.2015, 12:45, "lammps sina" <[email protected]>:

what ?
***The meaning of point is zone

I think the simplest (not the only possible) approach is to use the compute reduce/region command: in "sum" mode


06.04.2015, 15:00, "lammps sina" <[email protected]>:

what ?
***The meaning of point is zone

rule #1 in science is to be precise in your questions and answers.
thus if you want good answers to your questions, you have to take the
time and ask precise, good, and unambiguous questions.

that being said, if you want to do what it appears that you mean to
ask, then the simple answer is that you will likely have to write a
custom fix or do postprocessing of your trajectory file. ...and before
doing that, you have to decide on how to define the "passing through
XXX" event, i.e. how to deal with the possible re-crossing due to the
vibrations of atoms around its average positions. e.g. to avoid double
counting you would need to set up two regions in your fix, add a tag
to atoms that are in the first region and count atoms with this tag
when they enter the second and remove the tag when they are counted.
the regions must be wide enough to catch even the fastest moving atoms
and far enough apart from each other to only count the recrossings
that you want to count (e.g. through periodic boundaries).


Ah, this answers the question from another point of view.