fix heat/ehex for NEMD simulation

Dear all,

We are implementing fix heat/ehex command to heat a specified region
(source). However, based on the description of the fix, an energy flux
is generated by rescaling velocities in the hot and cold regions. The
cold region is not explicitly defined in our input file, instead we
use a Langevin thermostat to represent the sink. Following are my two

(1) Can this fix be used "only" to heat the source region?

(2) Will the energy balance of the system be affected by this fix, if
a thermostat is applied to another region in the system?


I suggest you study the example input script in
examples/HEAT/in.lj.ehex. Also see the README
file in that dir.

You will see the fix ehex is used twice, once for
a hot region, once for a cold region.