tabulated bond potential behavior outside of range

Message: 6
Date: Thu, 20 Oct 2016 10:23:53 -0400
From: Axel Kohlmeyer <[email protected]>
Subject: Re: [lammps-users] tabulated bond potential behavior outside
  of range
To: "K. Michael Salerno" <[email protected]>
Cc: "[email protected]"
  <[email protected]>
Message-ID:
  <[email protected]>
Content-Type: text/plain; charset=UTF-8

[ … ]

i don't see much of a benefit in your suggestion. once you are "off
the chart" things are broken anyway. nothing is keeping you from
creating a with a larger range, that implements the behavior you want.
once a bond is stretched beyond the communication cutoff, it will
possibly get "lost" anyway.

other tabulated potentials, e.g. pair style table stop with an error
(which is what i would personally favor in these situations).

I’m working with Michael on the system where this came up, and I’d just like to reinforce one point, which is that what LAMMPS does now is not even internally consistent. I’d be fine with returning an error, as you suggest, but returning a force that’s not equal to the derivative of the energy that is also returned seems like the worst solution.

                  Noam

[...]

i don't see much of a benefit in your suggestion. once you are "off
the chart" things are broken anyway. nothing is keeping you from
creating a with a larger range, that implements the behavior you want.
once a bond is stretched beyond the communication cutoff, it will
possibly get "lost" anyway.

other tabulated potentials, e.g. pair style table stop with an error
(which is what i would personally favor in these situations).

I’m working with Michael on the system where this came up, and I’d just like to reinforce one point, which is that what LAMMPS does now is not even internally consistent. I’d be fine with returning an error, as you suggest, but returning a force that’s not equal to the derivative of the energy that is also returned seems like the worst solution.

ok. i've implemented such a check. it will hopefully soon show up on
github in a pull request for steve to merge (provided the ongoing DNS
DDoS allows it).

axel.