def resume(self, options=None):
"""
"""
ReplicaExchange.resume(self, options=options)
#
# Cache Context and integrator.
#
# Use first state as reference state.
state = self.states[0]
# If temperature and pressure are specified, make sure MonteCarloBarostat is attached.
if state.temperature and state.pressure:
forces = { state.system.getForce(index).__class__.__name__ : state.system.getForce(index) for index in range(state.system.getNumForces()) }
if 'MonteCarloAnisotropicBarostat' in forces:
raise Exception('MonteCarloAnisotropicBarostat is unsupported.')
if 'MonteCarloBarostat' in forces:
barostat = forces['MonteCarloBarostat']
# Set temperature and pressure.
barostat.setTemperature(state.temperature)
barostat.setDefaultPressure(state.pressure)
barostat.setRandomNumberSeed(int(np.random.randint(0, MAX_SEED)))
else:
# Create barostat and add it to the system if it doesn't have one already.
barostat = openmm.MonteCarloBarostat(state.pressure, state.temperature)
barostat.setRandomNumberSeed(int(np.random.randint(0, MAX_SEED)))
state.system.addForce(barostat)
