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Feature #2910

Mixed scaling for 1-4 interactions

Added by Alexey Shvetsov 7 months ago. Updated 6 months ago.

Status:
New
Priority:
Normal
Assignee:
-
Category:
preprocessing (pdb2gmx,grompp)
Target version:
-
Difficulty:
uncategorized
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Description

Hi!

Some forcefield like Glycam uses fudgeQQ and fudgeLJ as 1.0. However this forcefield supposed to be compatible with Amber family forcefileds. But in that case its not possible to use this combination in Gromacs because 1-4 mixed scaling not supported.

I think it can be implemented like this
1. make fudgeQQ and fudgeLJ arrays (changes mainly in topio)
2. attach fudgeQQ and fudgeLJ to atoms (need to modify format of ff*.itp files, may be need to add aditional section)
3. Make gromacs topio works with this arrays (changes in topio)

Another possible solution is to add possibility of stacking forcefields.

History

#1 Updated by Berk Hess 7 months ago

The latest version of ACPYPE supports this for GROMACS. I assume they to this by providing the LJ-14 parameters for each interaction individually. I don't know if there is a simpler solution than that.

#2 Updated by Alexey Shvetsov 7 months ago

Do you mean this version by 'latest' https://pypi.org/project/acpype/

#3 Updated by Berk Hess 6 months ago

No, I mean this version: https://github.com/alanwilter/acpype

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