[gmx-users] How to add another electrostatic summation method in Gromacs
Mark.Abraham at anu.edu.au
Tue Mar 24 06:55:25 CET 2009
Shuangxing Dai wrote:
> Hi, all,
> I was wondering how to add another electrostatic summation
> method--Wolf summation into Gromacs. Wolf summation is a treatment for
> summation of Coulombic energy. Since the formula of total potential
> energy for each ion is known, how to add this into Gromacs? According to
> Chapter 7, I should give the f(x) and f'(x). The formula of f and f'
> depends on the neighbours and varies from ion to ion, and I can not give
> f and f' without calculation.
If you have a functional form that depends only on pairwise distance and
two atom types, then you can use the GROMACS table lookup machinery.
> Since Wolf method uses the same error
> function as Ewald summation, it might be easier and possible to
> implement Wolf into Gromacs. If so, which files need to be modified?
> Hope I put my question clearly. Thank you in advance for suggestions and
Evaluating erfc is not the core issue - but GROMACS does the evaluation
of terms for the direct-space Ewald contribution via table-lookup. The
big deal is whether you need a custom non-bonded kernel, and then
whether you can make it run fast. You might need to post a link to some
details of this summation method to get useful help.
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