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Bug #657

Problem of the function 'do_constraint' in file pull.c

Added by Yong Nam almost 9 years ago. Updated over 8 years ago.

Status:
Closed
Priority:
Normal
Assignee:
Category:
-
Target version:
Affected version - extra info:
4.5.3
Affected version:
Difficulty:
uncategorized
Close

Description

I have frequently used pull code of GROMACS with constraint and distance geometry.
Recently, I got a chance to take a look at the source code of 'do_constraint' function and think that there is an error for the iteration for shake algorithm.
(i.e. "while (!bConverged && niter < max_iter)" loop)
Once the last constraint group satisfies the given constraint, the current code stops the iteration even if the rest groups don't satisfy the given constraints. (I tested this for distance geometry at least, but I think that direction, direction_periodic and cylinder geometries have the same problem.)
This problem cannnot be ignored if we have multiple constraint groups.

Please double-check and address this issue to the next version of GROMACS.

Thanks,

Associated revisions

Revision c85af332 (diff)
Added by Berk Hess over 8 years ago

fixed convergence of multiple pull constraints

With multiple constraint pull groups, only the convergence
of the last group was checked. This fixes #657

History

#1 Updated by Mark Abraham over 8 years ago

  • Assignee set to Berk Hess
  • Target version changed from 4.5.1 to git master
  • Affected version - extra info set to 4.5.3

This looks like it's been broken for a few years. As Yong says, the iteration will terminate whenever the final constraint group sets bConverged = TRUE, without reference to the status of other groups.

#2 Updated by Rossen Apostolov over 8 years ago

  • Target version changed from git master to 4.5.5

#3 Updated by Berk Hess over 8 years ago

  • Status changed from New to Closed

I fixed it.

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