elimination of torque during the simulation

LAMMPS LAMMPS Mailing List Mirror
1

It is possible to elimiate torque of a certain group of atoms using “volocity”.
However, it can be peformed only at initial time.
If I’d like to eliminate the torque at every step during simulation, what should I do for it?

Thanks for your helps in advance.
Best regards,

Luke

2

You'd have to write a fix to do this, something
like fix setforce, only fix settorque.

Steve

3

I wrote a fix addtorque some time ago (see lammps mail list archive
Dec 03 2010). It should not be very difficult to update it to make it
work with the latest version of lammps, and generalize it to fix
avetorque or fix settorque...

Best,
Laurent

4

Hi, Steve and Laurent,

I used “fix settorque” but it gave error message of “invalid fix style”.
fix commands list also showed that there is not fix settorque command (or similar one).
If there is fix command corresponding to it, would you let me know of it, please?

Best regards,

Luke

5

2011/7/31 JhonY. I. <[email protected]...>:

Hi, Steve and Laurent,

I used "fix settorque" but it gave error message of "invalid fix style".
fix commands list also showed that there is not fix settorque command (or
similar one).

please pay attention!!

laurent implemented this feature, but it is not (yet) part of the
lammps distribution
and he pointed out where you can get it. of course you'll need to add
the code to
your lammps source tree, adapt it to the current coding conventions
and low-level
API and then compile a new lammps binary.

he did already most of the work, now you have to do the small bit that is left.

If there is fix command corresponding to it, would you let me know of it,
please?

this is not how open source software packages work. if _you_ want
or need something _that_ desperately, then _you_ have to make it
happen. there are very few exceptions where somebody will do the
work for your (e.g. because it is easy to do). in this case, you get
what you want presented on a silver platter. please show some
respect to laurent's efforts and generosity.

thanks,
    axel.

6

I misunderstood your replies and I am sorry for it, Laurent and Steve.
Thanks for the indication on it, axel.
I will check the code.

Cheers,

Luke

7

Just added these in a USER-MISC dir as a patch today.
Sorry for the delay, Laurent ...

Thanks,
Steve