Hi Andrew, thanks a lot for your email. I am using LAMMPS myself a lot due to all the features it has, which Gromacs hasn't. But as I said before it is all about time and interest. karthik was literally the first user asking for LAMMPS support. I am willing to help as much as I have time, but my own research focus has changed at bit over the last year. Patches are very welcome and I will give advice where ever I can.
There are two other aspects to LAMMPS as an MD backend. 1.) VOTCA provides (among other tools ) an engine (csg_inverse) which run the MD backend over many iterations and does the potential updates. If you want to do more advances and flexible MD simulations it seems more logical to call VOTCA from the inside of LAMMPS or a python script running LAMMPS. 2.) VOTCA implements IBI only for bonded and non-bonded 2-body interaction. One would have to develop and implement a version of IBI for 3/4-body non-bonded tabular potentials first. Another choice would be to use an optimizer (as implemented in VOTCA 1.3-dev) instead of IBI to find the best parameters for any non-tabulated potential, but again then it is maybe smarter to call VOTCA from inside LAMMPS. Cheers, Christoph 2012/8/27 Andrew Jewett <[email protected]>: > On Monday, August 27, 2012 11:12:54 AM UTC-4, Christoph Junghans wrote: >> >> On the other hand the only reason to use LAMMPS with VOTCA would be if >> you want to use feature, which is not implemented in Gromacs. IBI on >> non-bonded 3-body interactions is the only thing I could think of. >> For non-bonded 2-body interactions Gromacs is usually sufficient. > > > Okay, so I heard that I heard that and I thought I'd chime in. > > Tabulated 4-body bonded interactions are also available in LAMMPS: > http://lammps.sandia.gov/doc/dihedral_table.html > (Somebody here might find this useful.) > > You can also use arbitrary-length Fourier-series to accomplish the same > thing: > http://sourceforge.net/mailarchive/message.php?msg_id=29360634 > (This is kind of a hack, but it works. unfortunately right now the "charmm" > dihedral style LAMMPS only allows for integer angle offsets (in degrees) > which limits its usefulness.) > > Although I haven't tried it, you should be able to use all of these dihedral > potentials for improper interactions as well. > http://lammps.sandia.gov/threads/msg21689.html > > I hope this is useful to someone. > > Actually, the tabulated angle potentials are a relatively minor feature. > LAMMPS is nifty for other reasons. (Serious limitations notwithstanding, > LAMMPS is very flexible and end-users can write their own force-field > styles.) > Cheers > > Andrew > P.S. Please forgive me if this message got posted twice. (I'm not sure if > my earlier post made it to the list.) > > -- > You received this message because you are subscribed to the Google Groups > "votca" group. > To view this discussion on the web visit > https://groups.google.com/d/msg/votca/-/pGzee-S1nXoJ. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/votca?hl=en. -- Christoph Junghans Web: http://www.compphys.de -- You received this message because you are subscribed to the Google Groups "votca" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/votca?hl=en.
