Re: FEP: How check equilibration sufficiency? calculate dG?

From: Jerome Henin (jhenin_at_cmm.chem.upenn.edu)
Date: Tue Oct 14 2008 - 16:00:24 CDT

> I would love using dG (cum. aver.), but is it really a good measure for
> convergence? Assume a system got stuck into a local minimum and only at the
> very end of the equilibration phase, it leaves that local minimum. This will
> not show up in a cum. average quantity. Are mere energy values any better to
> check for convergence? (I doubt because these numbers are soo large).

Actually, by this standard, there is no good measure for convergence
of any quantity from a simulation, or rather, there is no good measure
based solely on data from the simulation itself. In practice, though,
local convergence can be probed by statistical methods (like bootstrap
or jackknife algorithms). But I agree that this is not the final
answer to the question: "what is the significance of my simulation
data?". That can only be appraised with some physical intuition and
knowledge of the system. That's why we are still in business...

Best,
Jerome

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