[gmx-users] langevin dynamics

[Gerrit Groenhof (RUG)]

I think you do not use the bd_fric in combination with sd, but with bd, 
the friction is set by the tau_t instead. Did you als use different 
parameters for that?

For bd, you would use the friction bd_fric to set the ld friction, but 
not for sd, but I could be wrong here...

Gerrit

syma wrote:

>Hi,
>
>I have been having a few problems running Langevin dynamics and was
>wondering if anyone can help.
>
>I have run both atomistic and coarse grain LD simulations in gromacs 3.1 3.2
>and 3.3. The puzzling thing is that changing the value of the frictional
>constant makes no difference to the simulations. Ie RMSD values are EXACTLY
>the same when simulations are run with different frictional constants.
>
>I have used gmxdump to analyse the tpr files- the correct values for the
>frictional term does seem to be picked up. The mdp file I have been using is
>attached. If anyone can see anything obviously wrong with the file I would
>appreciate your advice.
>
>Best wishes,
>
>-Syma 
>
>***************************************************
>
>Dr Syma Khalid                                  
>Department of Biochemistry,       
>University of Oxford                       
>South Parks Road,
>Oxford
>OX1 3QU
>U.K.
>
>
>
>***************************************************
>
>
>  
>
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