Nose-Hoover conserved energy is incorrect for non-integer ndof
When using Nose-Hoover thermostat, the number of degrees of freedom in temperature groups are casted to integer when calculating the conserved energy. In the original implementation, the number of degrees of freedom was used as
real, but the variable type was changed to
int during refactoring in f2854f89.
Somewhat related to #3796 (closed).