Re: [ESPResSo] using rigid bonds

[Christoph Junghans]

Hi Ana,

the tolerances are relative, what means a bond is conserved when

abs(1-r/R) < tolerance

where r is the distance you have and R is the wanted distance.
Put something like 0.001 there.

Because the distance is fixed also the velocity of the particles have to 
be the same, that is where the velocity tolerance comes into play.

And be careful the pressure correction is NOT taken into account, so 
either you build it in yourself or use molecular pressure.

Bye,

Christoph


Ana Vila Verde schrieb:
> Dear Espresso users/developers,
>
> I am interested in trying rigid bonds in espresso.  I had a look at the 
> documentation but I need a little more information: in what units should 
> I input the positional tolerance and velocity tolerance?  Can anyone 
> provide a short explanation about what is the meaning of velocity 
> tolerance in this context?  I am not familiar with the algorithm used to 
> implement rigid bonds, so I don't know why we need a velocity tolerance.
>
> Thank you for your attention.  Best regards,
>
> Ana

--
Dipl.-Phys. Christoph Junghans
Max Planck Institute for Polymer Research
Theory Group
POBox 3148
D 55021 Mainz, Germany

Phone: +49 6131 379 335
Web: http://www.mpip-mainz.mpg.de/~junghans