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[lammps-users] about a model
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[lammps-users] about a model

From: "htc" <619771202@...1204...>
Date: Mon, 6 Nov 2017 20:57:41 +0800

xdddddd  ok  i will try the second way first. It is too  hard for me to extend the code in the present.


please use "want to" not "wanna". the latter always conjures up the image of a crying small child that doesn't get to play with its favorite toy.

On Mon, Nov 6, 2017 at 7:38 AM, htc <619771202@...1204...> wrote:
if i model all particles as ellipsoids ,and take the sphere as special case of ellipsoid.
that means i should use"hybrid dipole ellispoid" , and that means i cannot use"fix nve/sphere update dipole" to update the dipole with the"sphere"?
if i also wanna to update the dipole,what should i do?

​well, you could extend the fix nve/asphere code to also handle dipole.
otherwise you would have to keep sphere as atom style and would have to set up a complex set of interactions with pair style hybrid/overlay.
the basic issue remains: you have to figure out a way to treat all "mixed" interactions properly.




On Mon, Nov 6, 2017 at 4:08 AM, htc <619771202@...1204...> wrote:
i wanna a model that contain sphere with dipole and ellipsoid without dipole,how do i use the command"atom style"?
Can i write this "atom_style  hybrid dipole sphere ellipsoid  " ?
Because i have to use the "fix nve/sphere update dipole" to describe sphere with dipole.
But for "hybrid",when you set the arguments of each atom,you have to list them as follows "atom-ID  atom-type x y z sub-style1 sub-style2...".
So i just donnot how to set the args,if i have to use "fix nve/sphere update dipole" to update the dipole set onto sphere within a system which is a mixture of sphere with dipole and ellipsoid without dipole.

​you have to provide all properties for all atoms, even if they are not used by the individual pair style or fix.
in your particular case, the *real* worrying question is: how are you going to describe the interactions between the spheres and the ellipsoids?
the only consistent solution that i can imagine would be to model all particles as ellipsoids, as a sphere is just a special case of an ellipsoid.​ same for the dipole, you can just make the dipole vector (0,0,0) for particles without dipole.