Re: Kb, Ktheta values for TIP3P water model

From: Axel Kohlmeyer (
Date: Wed Aug 06 2014 - 15:28:23 CDT

On Wed, Aug 6, 2014 at 3:41 PM, Hadi <> wrote:
> In Monte Carlo, you do not need to use a constraint solver to implement the
> rigid models. This is what I like to emphasize: unlike MD, they can "easily"
> be implemented. There is no need to solve a constraint. So I think you are

no. no. no. please pay attention. in MD you can do rigid bodies
without constraints just as well and instead of solving constraints.
you just propagate the center of mass and the rotational degrees of
freedom. this works very well, and i am using it regularly. it just
isn't implemented in NAMD but it is available in many other MD codes.
in fact, there are MD codes that *only* support such rigid body
propagators and do not have a constraint solver at all.

> mistaken: "the difference you were referring to is the difference between a
> rigid body propagator and using a constraint solver and that has little to
> do with MD vs. MC."

no. i stand by this sentence. you seem to be forgetting that NAMD is
not every MD program.

> I agree the term rigid model used in this thread is the one which uses the
> bond constraints and the discussions pertain to the corresponding methods.

again, you are missing the point i am criticizing. it is not what the
discussion started with that i have an issue with, but your wholly
unjustified, unproven, and incorrect generalizations.


> Thanks a lot for your comments.
> Hadi

Dr. Axel Kohlmeyer
College of Science & Technology, Temple University, Philadelphia PA, USA
International Centre for Theoretical Physics, Trieste. Italy.

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