-- Examples of i-PI working with LAMMPS -- -- Example with Tersoff graphene potential -- Uses the Tersoff parameters of Lindsay and Broido PRB 81, 205441 (2010) to run a short simulation of graphene with the LAMMPS MD code. -- Example with the q-TIP4P-F water potential -- * This gives an example of water with the q-TIP4P-F potential of Scott Habershon, Thomas E. Markland and David E. Manolopoulos, J. Chem. Phys., 131, 024501, (2009). * State point: (N, V, T) = (216 water molecules, 43737 a_0**3, 298 K) * This demonstrates the convergence of the kinetic and potential energy using the ring polymer contraction (RPC) method of Thomas E. Markland and David E. Manolopoulos, J. Chem. Phys. 129, 024105, (2008), and the PIGLET method of Michele Ceriotti and David Manolopoulos, Phys. Rev. Lett., 109, 100604, (2012). ** Run the examples automatically: * First, it is necessary to patch and compile LAMMPS, and create a make.in file containing the path to the executable and i-pi, e.g. LAMMPS:=~/bin/lmp_serial IPI:=~/bin/i-pi * The runs can be done automatically using the Makefile provided. The make targets are self-explanatory. To run the RPC example, for instance, just type: $ make h2o-rpc * To clean up output files: $ make clean ** Run the examples manually: * Go back to the example directory and run $ python path/i-pi input.xml the wrapper will start and sit waiting on the UDS /tmp/ipi. * Open a separate terminal and run the LAMMPS driver code using: $ path/lammps/src/lmp_serial < in.water For the RPC run, instead use: $ path/lammps/src/lmp_serial < in.water_longrange $ path/lammps/src/lmp_serial < in.water_shortrange You can run multiple instances of the code; it is so fast that parallel scaling won't be appreciable. * If your system does not support Unix domain sockets, just set in input.xml <socket mode="unix"> <port> port_no </port> To make the client socket connect, the in.water file should be changed so that it has the line: fix 1 all driver hostname port_no where hostname is the address the socket is binding to; either graphene, piglet_2, piglet_4, piglet_8, rpc_long, rpc_short or no_rpc depending on the run.