[gmx-developers] PR pressure control / constraints ...

[ANick at t-online.de]

Dear Michael and all others in the list,

last month (on 3rd of  April) you wrote some thoughts about
Parrinello-Rahman pressure control to this list. Do the problems
you described mean that I cannot expect to get the right density
after a long MD with PR pressure coupling?
( I calculated the system density with the g_energy tool.)
Do I end up with a different density when using i.e. Berendsen
pressure coupling?
I observed some deviation in the density of simple PE systems
after equilibration with GROMACS  - isotropic PR pressure
coupling and all bonds constrained - in comparison to
some collegues using other simulation packages
(both of us used identical force fields and simulation parameter 
as far as possible).

Thanks for your opinion,
Gitta

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Birgitta Nick
Lab. of Non-Metallic Materials
Polytechnical University of Madrid, SPAIN