Constraint in stochastic dynamics

User discussions
1

GROMACS version:
GROMACS modification: Yes/No
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Hi,
I’m using stochastic dynamics to simulate a membrane with the Dry MARTINI force field. Although I’m employing a relatively large timestep of 40 ps, the simulations run smoothly and never crash. My question is: do I really need to apply constraints, given that they slow down the simulations by correcting particle positions twice per timestep?

Many thanks,

Many thank

2

This is a question for Martini, not GROMACS. The general answer is that you need to apply constraints in the same way as was used to parametrize the force field.

3

Thanks for the reply.
In this sense, I don’t need to use constraints since There are no [ constraints ] entries in Dry Martini lipid .itp files. Right ?

4

I am not an expert on Martini, so I will not speculate much here. But I would think that if Martini uses constraints, they would be in the generated itp files, I wouldn’t expect that the user would need to choose anything (like the mdp option constraints=h-bonds for atomistic force fields).