i have to thank you for your help in the very beginning. I am a new learner
of lammps.Without your explain,it may take me more time to know lammps well.
And for the previous question,there still some thing that confuse me.
I use"fix langevin" in "atom_style ellipsoid" before,and in that simulation
i use "fix setforce" "fix enforce2d",the system confine in 2d,and operates
why things go wrong for rigid body.....
because there is an issue with the fix rigid implementation that needs
to be corrected when using rigid bodies in 2d with the langevin flag.
i have submitted a pull request, with changes to address this
particular issue: https://github.com/lammps/lammps/pull/570
for 2d simulations, there should be no need to use fix setforce to
zero out the z-direction force component, fix enforce2d will do that
Another question,the command "fix setforce NULL NULL 0",set Fz=0.Does the
setting always working during the simulation?i mean,do the command set Fz
to zero during the simlation?The particle only receive the force along x
axis and y axis whatever other settings?If so,why i use
command"langvein",and "fix setforce" doesnt work?Do the command "fix
enforce2d" the same as the command"fix setforce"?
i don't have time to explain the entire logic of the LAMMPS source
code and its commands to you. in addition, you are making connections,
that do not exist or make sense. if you do want answers to these kind
of questions, you have to dig into the source code and figure it out
by yourself. what LAMMPS is supposed to do is documented in the
manual. i am happy to discuss if LAMMPS behavior differs from what is
documented in the manual and you provide easily reproducible proof.
BTW: please also note, that i *strongly* dislike the phrase "does not
work". it is vague, non-descriptive, and counterproductive. it can
mean anything from "LAMMPS crashes hard" (e.g. with a segmentation
fault), over "LAMMPS refuses to run my input deck" to "LAMMPS does not
produce the expected result" (which may actually be correct).
in the future, please be specific or else you will see your requests
for help ignored.