[lammps-users] checking conservation of extended hamiltonian for rigid body nvt dynamics

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1

Trung - I posted your your update to fix rigid/nvt as a 28Nov10
patch. Thanks for adding this.

I have a question though for you and Aidan. I thought the idea
with these thermostat energy calculations was to provide a
quantity that allowed the cummulative energy change to be
monitored, added to the system energy, and thus conservation
tracked over time. This is what fix temp/rescale and fix langevin
do for example. However both fix nvt and fix rigid/nvt appear
not to be doing the cummulative part. I.e. they just calculate
energy change on the current step, but don't add it to a running
total? Is this intentional, or am I misunderstanding how this
output quantity is supposed to be used?

Steve

2

It's the same idea. The difference is that the accumulated energy is an
analytic function of the current state, so no explicit accumulation is
required.

3

Correct. For fix rigid/nvt, the conserved quantity can be calculated by summing the output of compute_scalar() and potential energy, as commented in the code.

-Trung

Quoting "Thompson, Aidan" <[email protected]>: