[gmx-developers] force field reorganization

Berk Hess hess at cbr.su.se
Mon Jan 25 15:52:28 CET 2010


Ah, good that you mention this.
I thought about this, but forgot about it.
I will add a check such that is always uses the first entry and warns you
when it ignores are second one.
Your working dir will always be read first.

Another feature is that you can now have different bonded settings
(bond, angle, dihedral types, nrexcl, etc.) for rtp entries in different
files.
But within each moleculetype only one setting can be used, pdb2gmx
checks this.

Berk

Tsjerk Wassenaar wrote:
> Hi Berk,
>
> Sounds like a good idea. So it would also be easy to add ligands, as
> it would only require to put a ligand.rtp to the directory, without
> editing the original files? But what will happen if a certain residue
> is defined in different files? Will it issue a warning, or an error,
> something else?
>
>
> Cheers,
>
> Tsjerk
>
> On Mon, Jan 25, 2010 at 3:34 PM, Berk Hess <hess at cbr.su.se> wrote:
>   
>> Hi,
>>
>> I have made some changes in pdb2gmx to better organize all the force
>> field files.
>> But before I commit, I would like to have some feedback from the GROMACS
>> community.
>>
>> If have now made it such that force fields are all in separate
>> directories and there is
>> no longer an FF.dat file.
>> Force fields are now detected by pdb2gmx by a filename in a subdirectory
>> as follows:
>> <ffname>.ff/forcefield.itp
>> For example for OPLS:
>> oplsaa.ff/forcefield.itp
>> If the directory also contains a file forcefield.doc, the first line of
>> this file is assumed
>> to be a short description of the force field and this is printed
>> (previously this was in FF.dat).
>>
>> pdb2gmx then reads any files ending on .atp, .r2b, .rtp, .tdb, .hdb,
>> both from the force field directory and the current working directory.
>> The only mandatory files are one .atp file and one .rtp file.
>> Termini from .tdb files are only applied to rtp entries from .rtp files
>> with the same base file name.
>> The general idea is to have, for instance:
>> atomtypes.atp
>> aminoacids.rtp
>> aminoacids.n.tdb
>> aminoacids.c.tdb
>> aminoacids.hdb
>> dna.rtp
>> dna.n.tdb
>> dna.c.tdb
>> dna.hdb
>>
>> Especially useful for AMBER, you can have .r2b files to map residue
>> names to building block names,
>> depending on the protonation state and if in termini or not.
>> Also useful for AMBER, you would not longer be required to make tdb files.
>> pdb2gmx checks if there are no dangling bonds due to missing termini.
>>
>> For backward compatibility of grompp there would still be a file such as
>> ffoplsaa.itp
>> in the lib dir, which would simply #include ffoplsaa.ff/forcefield.itp,
>> similarly there will
>> be spc.itp, tip3p.tip, ions.itp etc.
>>
>> Are there any objections or comments?
>>
>> Berk
>>
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>>     
>
>
>
>   




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