i-PI path integral MD with AMS¶
Note: This example requires AMS2023 or later.
i-PI can be used to run for example path integral molecular dynamics. The example shows how to run thermostatted ring polymer molecular dynamics for a water molecule together with the UFF force field.
For more information about i-PI, refer to the i-PI documentation and examples.
The below example only runs on Linux as it uses a unix socket.
i-PI is not included with AMS and is not supported by SCM.
#!/usr/bin/env amspython from ase.calculators.socketio import SocketClient from ase.io import read from scm.plams import Settings, finish, init from scm.plams.interfaces.adfsuite.ase_calculator import AMSCalculator """ Example illustrating how to use AMS as a client together with i-PI. The i-PI configuration in input.xml sets up a short ring-polymer molecular dynamics (RPMD) simulation. The connection between server and client is of type 'unixsocket' (a file in /tmp). This example will only run on Linux. The settings below set up AMS to use the UFF force field to calculate the energy, forces, and stress tensor of whatever system the i-PI server requests and return them to i-PI. AMS is run in "AMSWorker" mode (interactive mode), which means that AMS does **not** shut down and start up again between calculations. To run this example, * modify run-server.sh to provide the correct path to the i-pi executable, * sh run-server.sh * In a different terminal: $AMSBIN/amspython run-ase.py """ def main(): init() use_stress = False atoms = read('firstframe.xyz') sett = Settings() sett.input.ams.Task = 'SinglePoint' sett.input.ams.Properties.Gradients = 'True' sett.input.ams.Properties.StressTensor = str(use_stress) sett.input.forcefield.type = 'UFF' sett.runscript.nproc = 1 with AMSCalculator(settings=sett, amsworker=True) as calc: atoms.set_calculator(calc) client = SocketClient(unixsocket='driver-irpmd-16') # socket should match the one given in input.xml client.run(atoms, use_stress=use_stress) finish() if __name__ == '__main__': main()