what't the difference bwteen NVT-Nose-Hoover-chain and NVT-Nose-Hoover in 2015?

[wot19920302]

Dear Quantumstaffs:
           I practice the tutorial from this link: http://docs.quantumwise.com/tutorials/md_basics/md_basics.html.       When I use NVT-Nose-Hoover method  in 2015.1 to calculate Si bulk, the results seems different from datas  given  by tutorials. But when I use NVT-Nose-Hoover-chain in ver2015.1 or  NVT-Nose-Hoover in 2016.3, the results are consistent with  datas  given  by tutorials. Could anyone explain this problem? what't the difference bwteen NVT-Nose-Hoover-chain and NVT-Nose-Hoover in ver2015.1?
             Best

[Julian Schneider]

The NVTNoseHooveChain in ATK-2015 is essentially the same as the new NVTNoseHoover thermostat in ATK-2016.
The old NVTNoseHoover in ATK-2015 thermostat does not exists any more in ATK-2016, as it was using an older algorithm which is not state-of-the-art.
In ATK-2015 you should use the NVTNoseHooverChain thermostat.

[wot19920302]

thank you, sir!