fix adapt with lj/cut/coul/cut

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1

Dear Lammps Users,

I have recently started using fix adapt and compute ti. Separately,
lj/cut and coul/cut work well with fix adapt.

Is it possible to use fix adapt to scale LJ and coulombic interactions
simultaneously (pair_style lj/cut/coul/cut)?

Thanks,
Manish Agarwal
<[email protected]...>
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2

I remember reading on a different mailing list that this would be a bad idea. You want the two types of interactions decoupled do TI. Axel.

3

Indeed, Axel!

However,
(1) the reference mentioned in the LAMMPS manual does this - Eike and
Maginn, Journal of Chemical Physics, 124, 164503 (2006). uses this.
(2) If I were to decouple them, I would still need to fix one and
change the other - hence needing the fix adapt and compute ti versions
for lj/cut/coul/cut?

Thanks,
Manish Agarwal
<[email protected]...>
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4

Indeed, Axel!

However,
(1) the reference mentioned in the LAMMPS manual does this - Eike and
Maginn, Journal of Chemical Physics, 124, 164503 (2006). uses this.

(2) If I were to decouple them, I would still need to fix one and
change the other - hence needing the fix adapt and compute ti versions
for lj/cut/coul/cut?

have you tried using pair_style hybrid/overlay?

axel.

5

If you look at one of the pair styles supported by fix adapt,
you will see it is a quite simple piece of code to add, to
add support. I suggest you talk to Sai (CCd) - if he agrees
it makes sense to use with LJ + Coul, then it can easily
be added.

Steve

6

Steve is quite right, it can easily be added. You have to add ‘scale’ variable to pair_lj_cut_coul_cut.cpp and pair_lj_cut_coul_long.h ( as in pair_coul_cut.* )

Recently I’ve done it for lj/cut/coul/long - it takes 5 minutes of coding.

Regards,

Grigory

2012/9/18 Steve Plimpton <sjplimp@…29…>

7

Thank you everyone!

Axel: I have tried hybird/overlay and it works well.

Steve, Grigory and Sai: I would also be modifying the code as advised!
lj/cut/coul/long is definitely the ultimate target.

Best wishes,
Manish Agarwal
<[email protected]...>
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