[gmx-users] Avoiding calculation on some degrees of freedom

[gianluca.santarossa]

>> For example, if atoms A and B are bonded, and some force
>> acts on A, I want to keep the A-B distance constant, 
>>moving B
>> as much as A, and B not affecting force on A.
> Apart from constraints you mean?
Well, AFAIK contraints are not applied on angles or 
dihedrals.

My idea was to 'simplify' a topology of a non-proteic 
molecule
to move it in a subspace of the whole phase space, for 
example
allowing only dihedrals to change, and see what happens.
So, there are some connections I want to take into account 
without
calculation of forces from them.

Thanks
Gianluca