[gmx-users] switching and shifting in GMX 4.6 on GPUs

[Berk Hess]

Hi,

I am not a fan of especially switching the potential, as that produces artifacts.
Shifting is less harmful, but unnecessary in nearly all cases.
But I do realize some force fields require this (although you can probably find a cut-off
setting at which results would be very similar).
Another reason for not implementing everything right away, is that it would increase the number
of CPU and GPU kernels by a factor 3.

What type(s) of LJ cut-off treatments would you consider most important?
I know that CHARMM uses a switch function and Martini uses shift.

Cheers,

Berk

----------------------------------------
> From: jesorensen at ucsd.edu
> Date: Thu, 24 Jan 2013 12:43:30 -0800
> To: gmx-users at gromacs.org
> Subject: [gmx-users] switching and shifting in GMX 4.6 on GPUs
>
> Dear GMX developers,
>
> Thanks so much for the GMX 4.6 release. Testing on GPUs has shown impressive speed-ups.
>
> I have a question however, regarding the missing "switching and shifting" for non-bonded interactions.
> I looked at the developer zone website and saw this comment below:
>
> http://www.gromacs.org/Developer_Zone/Roadmap/GROMACS_4.6
> * Features currently not supported by the new GPU and SSE kernels:
> ** Switch and shift interactions (but those are not important, as there is an exact cut-off)
>
> While the statement maybe true that they are not "important", some force fields are very particular about the use of switching and shifting, as it is integral to the FF development.
> So to my question, is there a timeframe for these features being implemented?
>
> I realized things like this take time, so I am merely asking out of curiosity.
>
> Best regards,
> Jesper
>
>
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