[gmx-users] "constraints:none" segmentation fault

[Giorgos Karvounis]

Dear all,

I want to simulate a b-hairpin in spc water in a NVE ensemble. I
basically want to "reproduce" the simulation of beta-hairpin of
Thermistat from the extended conformation at 360 K ( A. Bonvin et al.
J.M.B (2000) 296,255-268).  I am using PME without any coupling
(neither  T nor P). I run first a position restraints run , with T
coupling on , then i turn it off for a md run. The problem is that the
temperature is gradually cooling down... looking at the user's list, it
seems that others faced the same problem and appartently a fisrt
approach to this problem is to use FLEX_SPC and "constraints: none". My
problem is that, when i use "constraints :none" in the .mdp file, after
50 steps , i get a segmentation fault and the run crashes.
So basically, after having read many emails about PME and energy
conservation, and still being quite confused about it, can you please
summarise wich are the best parameters for this type of run and if you
can tell me a possible reason for the segmentation fault?
I am grateful for any advice.

Thank you in advance

Giorgos