[gmx-developers] problem with FEP in CVS code

[David Bostick]

Hello,

I compiled the rc1 version today with cvs co -r release-3-3-patches gmx
but it seemed to have the same block error as before.  I wasn't sure what 
to check out, so I just went for today's head branch 
(VERSION 3.3.99_20050909), which should be close enough to rc1.

I found a problem when trying to do a FEP run transforming a blocked GLUH 
--> GLU in water. Here is what I observed:

1) When free_energy = no: a test run goes to completion
2) When doing the equivalent run with free_energy = yes as follows:

;Free Energy Perturbation
free_energy            = yes
init_lambda            = 0.0
delta_lambda           = 0.0

the exact same run crashes on the first step.  step-1.pdb shows the 
initial configuration and step0.pdb shows an apparently exploded system.
This happens with both an mpi version and a single-processor version.

I am able to do both runs 1 and 2 with an older version of gmx, so the 
problem is not in the topology I believe.

David


-- 
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David Bostick			       |
The Scripps Research Institute         |
Dept. of Molecular Biology, TPC 6      |
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