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

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?


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

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.


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