git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@14950 f3b2605a-c512-4ea7-a41b-209d697bcdaa

doc/html/_sources/fix_ipi.txt

@@ -0,0 +1,107 @@
+.. index:: fix ipi
+
+fix ipi command
+===============
+
+Syntax
+""""""
+
+.. parsed-literal::
+
+   fix ID group-ID ipi address port [unix]
+
+* ID, group-ID are documented in :doc:`fix <fix>` command
+* ipi = style name of this fix command
+* address = internet address (FQDN or IP), or UNIX socket name
+* port = port number (ignored for UNIX sockets)
+* optional keyword = *unix*\ , if present uses a unix socket
+
+Examples
+""""""""
+
+fix 1 all ipi my.server.com 12345
+fix 1 all ipi mysocket 666 unix
+
+Description
+"""""""""""
+
+This fix enables LAMMPS to be run as a client for the i-PI Python
+wrapper :ref:`(IPI) <IPI>` for performing a path integral molecular dynamics
+(PIMD) simulation.  The philosophy behind i-PI is described in the
+following publication :ref:`(IPI-CPC) <IPICPC>`.
+
+A version of the i-PI package, containing only files needed for use
+with LAMMPS, is provided in the tools/i-pi directory.  See the
+tools/i-pi/manual.pdf for an introduction to i-PI.  The
+examples/USER/i-pi directory contains example scripts for using i-PI
+with LAMMPS.
+
+In brief, the path integral molecular dynamics is performed by the
+Python wrapper, while the client (LAMMPS in this case) simply computes
+forces and energy for each configuration. The communication between
+the two components takes place using sockets, and is reduced to the
+bare minimum. All the parameters of the dynamics are specified in the
+input of i-PI, and all the parameters of the force field must be
+specified as LAMMPS inputs, preceding the *fix ipi* command.
+
+The server address must be specified by the *address* argument, and
+can be either the IP address, the fully-qualified name of the server,
+or the name of a UNIX socket for local, faster communication. In the
+case of internet sockets, the *port* argument specifies the port
+number on which i-PI is listening, while the *unix* optional switch
+specifies that the socket is a UNIX socket.
+
+Note that there is no check of data integrity, or that the atomic
+configurations make sense. It is assumed that the species in the i-PI
+input are listed in the same order as in the data file of LAMMPS. The
+initial configuration is ignored, as it will be substituted with the
+coordinates received from i-PI before forces are ever evaluated.
+
+Restart, fix_modify, output, run start/stop, minimize info
+""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
+
+There is no restart information associated with this fix, since all
+the dynamical parameters are dealt with by i-PI.
+
+Restrictions
+""""""""""""
+
+
+Using this fix on anything other than all atoms requires particular
+care, since i-PI will know nothing on atoms that are not those whose
+coordinates are transferred. However, one could use this strategy to
+define an external potential acting on the atoms that are moved by
+i-PI.
+
+This fix is part of the USER-MISC package.  It is only enabled if
+LAMMPS was built with that package.  See the :ref:`Making LAMMPS <start_3>` section for more info.  Because of
+the use of UNIX domain sockets, this fix will only work in a UNIX
+environment.
+
+Related commands
+""""""""""""""""
+
+:doc:`fix nve <fix_nve>`
+
+
+----------
+
+
+.. _IPICPC:
+
+
+
+**(IPI-CPC)** Ceriotti, More and Manolopoulos, Comp Phys Comm, 185,
+1019-1026 (2014).
+
+.. _IPI:
+
+
+
+**(IPI)**
+`http://epfl-cosmo.github.io/gle4md/index.html?page=ipi <http://epfl-cosmo.github.io/gle4md/index.html?page=ipi>`_
+
+
+.. _lws: http://lammps.sandia.gov
+.. _ld: Manual.html
+.. _lc: Section_commands.html#comm