Change doc folder src -> txt, rst -> src

doc/src/fix_python_invoke.rst

@@ -0,0 +1,93 @@
+.. index:: fix python/invoke
+
+fix python/invoke command
+=========================
+
+Syntax
+""""""
+
+
+.. parsed-literal::
+
+   fix ID group-ID python/invoke N callback function_name
+
+* ID, group-ID are ignored by this fix
+* python/invoke = style name of this fix command
+* N = execute every N steps
+* callback = *post\_force* or *end\_of\_step*
+  
+  .. parsed-literal::
+  
+       *post_force* = callback after force computations on atoms every N time steps
+       *end_of_step* = callback after every N time steps
+
+
+
+Examples
+""""""""
+
+
+.. parsed-literal::
+
+   python post_force_callback here """
+   from lammps import lammps
+
+   def post_force_callback(lammps_ptr, vflag):
+       lmp = lammps(ptr=lammps_ptr)
+       # access LAMMPS state using Python interface
+   """
+
+   python end_of_step_callback here """
+   def end_of_step_callback(lammps_ptr):
+       lmp = lammps(ptr=lammps_ptr)
+       # access LAMMPS state using Python interface
+   """
+
+   fix pf  all python/invoke 50 post_force post_force_callback
+   fix eos all python/invoke 50 end_of_step end_of_step_callback
+
+Description
+"""""""""""
+
+This fix allows you to call a Python function during a simulation run.
+The callback is either executed after forces have been applied to atoms
+or at the end of every N time steps.
+
+Callback functions must be declared in the global scope of the
+active Python interpreter. This can either be done by defining it
+inline using the python command or by importing functions from other
+Python modules. If LAMMPS is driven using the library interface from
+Python, functions defined in the driving Python interpreter can also
+be executed.
+
+Each callback is given a pointer object as first argument. This can be
+used to initialize an instance of the lammps Python interface, which
+gives access to the LAMMPS state from Python.
+
+.. warning::
+
+   While you can access the state of LAMMPS via library functions
+   from these callbacks, trying to execute input script commands will in the best
+   case not work or in the worst case result in undefined behavior.
+
+Restrictions
+""""""""""""
+
+
+This fix is part of the PYTHON package.  It is only enabled if LAMMPS
+was built with that package.  See the :doc:`Build package <Build_package>` doc page for more info.
+
+Building LAMMPS with the PYTHON package will link LAMMPS with the
+Python library on your system.  Settings to enable this are in the
+lib/python/Makefile.lammps file.  See the lib/python/README file for
+information on those settings.
+
+Related commands
+""""""""""""""""
+
+:doc:`python command <python>`
+
+
+.. _lws: http://lammps.sandia.gov
+.. _ld: Manual.html
+.. _lc: Commands_all.html