[gmx-users] Are the constraint forces included intheforcesoutputed in the

[Pu Liu]

>>>>   Could you please tell me if the constraint forces are included in the 
>>>>forces outputed in the trr file?
>>>
>>>Constraint forces are not included. We should state this somewhere in the 
>>>manual.
>>
>>I wondered about this before as well. Shouldn't we include them  anyway?
>>It is quite important when you use the forces for e.g. computing a
>
>You don't want to compute PMF from the forces in the trr file.
>You need a lot of sampling for a PMF and the trr would become far too big.
>Currently we have the pull code and free energy code, both with
>umbrella sampling and constraints for determining PMF's.
>I prefer to have F=-grad V in the trr file and not the constraint forces.

Thank you very much for all your helps.
That's great! The force without the constraint force is just what I want.
For free energy calculation, I will use thermodynamics intergration or pull 
code. Thank you for your kind suggestion.
>>I wondered about this before as well. Shouldn't we include them  anyway?
It might be a good idea to add an option to determine if writing the 
constraint force into trr file or not. How do you think?

-- Pu

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