[gmx-users] Lambda Weights from Expanded Ensemble Code

[Michael Shirts]

The simulated tempering options haven't been as well tested as the
hamiltonian expanded ensemble version.  The weights SHOULD be showing up in
the column that says -nan, but clearly they aren't.  If you file a redmine
issue, I may be able to take a look, but it might take a while to address.

On Wed, Jan 15, 2020 at 8:52 PM Daniel Kozuch <dkozuch at princeton.edu> wrote:

> Hello,
>
> I am interested in using simulated tempering in GROMACS (2019.5) under the
> expanded ensemble options. Is there a way to monitor the ensemble weights
> as the simulation progresses? I think in theory they are supposed to be
> printed out in the log file, but it is only printing 0, -nan, and inf:
>
>             MC-lambda information
>   N  Temp.(K)    Count   G(in kT)  dG(in kT)
> ...
>  36  359.105      118       -nan       -nan <<
>  37  366.880       96       -nan       -nan
>  38  374.852      107       -nan       -nan
>  39  383.026      129       -nan       -nan
>  40  391.407      166       -nan       -nan
>  41  400.000      199       -nan    0.00000
>
> Here are my relevant mdp settings:
> simulated-tempering             = yes
> nstexpanded                     = 500
> simulated-tempering-scaling     = exponential
> lmc-stats                       = metropolis-transition
> lmc-move                        = metropolis
>
> Any suggestions?
>
> Best,
> Dan Kozuch
> --
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