Andersen thermostat

In the method proposed by Andersen [64], the system is thermally coupled with a fictitious heat bath with the desired temperature. The coupling is represented by stochastic impulsive forces that act occasionally on randomly selected particles. The $NVT$ simulation with an Andersen thermostat is performed if MDALGO=1. The metadynamics with an Andersen thermostat is invoked by setting MDALGO=11. The collision probability is defined as an average number of collisions per atom and time-step. This quantity can be controlled by the flag ANDERSEN_PROB, see Sec. 6.62.3. The total number of collisions with the heat-bath is written in the file REPORT for each MD step.