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Task #2735

Allow gmx_genrestr to write correct position restraints for molecules after the first molecule

Added by Joe Jordan 15 days ago. Updated 11 days ago.

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

If you want to have position restraints for multiple chains in a protein, this is currently not allowed by gmx_genrestr. There is no reason for this and it is a simple change to a single line of gmxana/gmx_genpr.cpp.

With the current code,

for (i = 0; i < igrp; i++)
{
    fprintf(out, "%4d %4d %10g %10g %10g\n",
            ind_grp[i]+1, 1, fc[XX], fc[YY], fc[ZZ]);
}

the attached script fails to make the B chain restraints. But with a simple change,
for (i = 0; i < igrp; i++)
{
    fprintf(out, "%4d %4d %10g %10g %10g\n",
            i+1, 1, fc[XX], fc[YY], fc[ZZ]);
}

the script runs successfully. Additionally, the second version is the way writing position restraints (for all heavy atoms) in pdb2gmx works.

I might argue that this is actually a bug, but perhaps there may be some reason it needs to work this way that I don't know about.

posre.sh (915 Bytes) posre.sh simple script to demonstrate issue in gmx genrestr Joe Jordan, 11/05/2018 07:41 PM
chainTer.pdb (19.7 KB) chainTer.pdb input structure to script Joe Jordan, 11/05/2018 07:41 PM
ca.mdp (39 Bytes) ca.mdp input mdp file Joe Jordan, 11/05/2018 07:41 PM
posre.sh (1.38 KB) posre.sh Joe Jordan, 11/09/2018 12:19 PM

History

#1 Updated by Gerrit Code Review Bot 15 days ago

Gerrit received a related patchset '1' for Issue #2735.
Uploader: Joe Jordan ()
Change-Id: gromacs~master~Ifd849020da98b8052f0f965e53a079c6bddfc2d5
Gerrit URL: https://gerrit.gromacs.org/8654

#2 Updated by Joe Jordan 11 days ago

I tested this to make sure that mdrun also works and everything seems fine. I created a slightly more elaborate script to demonstrate this. I think it might be a good idea to turn this script into an integration test using the test fixtures and starting from a suitably equilibrated box.

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