[gmx-developers] free energy with PME

david.evans at ulsop.ac.uk david.evans at ulsop.ac.uk
Mon Dec 6 11:42:39 CET 2004

Dear developers,

I recently (Nov 23rd) checked out the CVS code and noticed that the
warning message
"You are using lattice sum electrostatics with free energy
integration. This might give wrong results, since the lattice
contribution to the free energy not calculated."
had been removed, and replaced with one which only appears when PPPM
is used rather than PME.

Does this mean that the PME electrostatics with free_energy = yes are
evaluated correctly (i.e. including the reciprocal part) in the CVS
FYI, I reran a system which I had previously done with version 3.2.1,
and found that my DeltaG values increased by around 30 kJ/mol for
both my free and bound ligands when using the CVS code. So the
overall DeltaDeltaG doesn't change much, but there does appear to be
a significant change in the electrostatics from somewhere.

I will hopefully be doing some serious production free energy
simulations in the near future, so I just wanted some confirmation
that I'd interpreted changes in the code correctly before starting to
use CVS on a large scale.


Dave Evans
University of London
School of Pharmacy

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