[gmx-developers] problems with trajectory reversal

[Anton Feenstra]

Jarek Juraszek wrote:
> Is there an easy way of reversing my trajectory or should I somehow 
> modify the code to get proper results? What is Gromacs doing with the 
> kinetic energy at the initialisation that it seems to increase ?

If you use twin-range cutoff with nstlist > 1, your trajectory will not
be reversible in principle, due to the interval between updating long-
range forces. Also, I think constraints may be problematic upon momenta
inversion (not sure about this, though).

Apart from this, numerical precision will prevent you from exact reversal
in any case, even in double precision. Is there a specific reason you need
this reversal? You already have the outcome by simply playing the forward
trajectory in reverse... ;-)


-- 
Groetjes,

Anton
  _____________ _______________________________________________________
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|  _   _  ___,| K. Anton Feenstra                                     |
| / \ / \'| | | Dept. of Pharmacochem. - Vrije Universiteit Amsterdam |
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