Perhaps the next most important choice is what kind of integration algorithm to use. Above we did a constanttemperature (NVT) algorithm (the actual algorithm is of the NosÃ©Hoover type). For constant energy (NVE) runs we create the integrator as follows, here passing only the timestep:
itg = IntegratorNVE(timeStep=0.0025)
(Technical note: this creates an object of the same type as IntegratorNVT,
but here it defaults to NVE mode—in fact in either case one can switch
thermostatting on or off using the SetThermostatOn()
method).
Additional integrators available in RUMD are listed below
Name of Integrator  Description  Arguments  

IntegratorNVE  The NVE Leapfrog algorithm.  timeStep 

IntegratorNVT  The NosHoover NVT algorithm.  timeStep, targetTemperature, thermostatRelaxationTime 

IntegratorNPTAtomic  NPT algorithm. (JCP 101, N 5, 1994) 
timeStep, targetTemperature, thermostatRelaxationTime, targetPressure, barostatRelaxationTime


IntegratorNVU  Algorithm conserving the total potential energy.  dispLength, potentialEnergy 

IntegratorMMC  Metropolis NVT Monte Carlo.  dispLength, targetTemperature 

IntegratorIHS  Energy minimization via the Leapfrog algorithm.  timeStep 

IntegratorSLLOD  Shear an atomic system in the xyplane using the SLLOD equations.  timeStep, strainRate 

IntegratorMolecularSLLOD  Shear a molecular system in the xyplane using the SLLOD equations.  timeStep, strainRate 

IntegratorNPTLangevin  Algorithm which generates the NPT ensemble using Langevin dynamics  timeStep, targetTemperature, friction, targetPressure, barostatFriction, barostatMass 