collapse multiple empty lines into a single empty line
This commit is contained in:
Axel Kohlmeyer
@ -6,7 +6,6 @@ python command
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Syntax
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""""""
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.. parsed-literal::
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python func keyword args ...
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@ -44,12 +43,9 @@ Syntax
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inline = one or more lines of Python code which will be executed immediately
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must be a single argument, typically enclosed between triple quotes
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Examples
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""""""""
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.. code-block:: LAMMPS
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python pForce input 2 v_x 20.0 return v_f format fff file force.py
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@ -110,10 +106,8 @@ A broader overview of how Python can be used with LAMMPS is given on
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the :doc:`Python <Python_head>` doc page. There is an examples/python
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directory which illustrates use of the python command.
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----------
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The *func* setting specifies the name of the Python function. The
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code for the function is defined using the *file* or *here* keywords
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as explained below. In case of the *source* keyword, the name of
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@ -162,7 +156,6 @@ of a python-style variable associates a Python function name with the
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variable. This must match the *func* setting for this command. For
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example these two commands would be self-consistent:
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.. code-block:: LAMMPS
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variable foo python myMultiply
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@ -195,10 +188,8 @@ include the string terminator). If the Python function generates a
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string longer than the default 63 or the specified *Nlen*\ , it will be
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truncated.
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----------
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Either the *file*\ , *here*\ , or *exists* keyword must be used, but only
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one of them. These keywords specify what Python code to load into the
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Python interpreter. The *file* keyword gives the name of a file,
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@ -226,10 +217,8 @@ later invoked, the function code must match the *input* and
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*return* and *format* keywords specified by the python command.
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Otherwise Python will generate an error.
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----------
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This section describes how Python code can be written to work with
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LAMMPS.
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@ -261,7 +250,6 @@ python-style variable associated with the function. For example,
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consider this function loaded with two global variables defined
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outside the function:
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.. code-block:: python
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nsteplast = -1
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@ -318,16 +306,13 @@ global temperature of the system, then you must insure all your Python
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functions (running independently on different processors) call back to
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LAMMPS. Otherwise the code may hang.
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----------
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Your Python function can "call back" to LAMMPS through its
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library interface, if you use the SELF input to pass Python
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a pointer to LAMMPS. The mechanism for doing this in your
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Python function is as follows:
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.. code-block:: python
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def foo(lmpptr,...):
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@ -347,7 +332,6 @@ string argument which is a LAMMPS input script command for LAMMPS to
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execute, the same as if it appeared in your input script. In this case,
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LAMMPS should output
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.. parsed-literal::
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Hello from inside Python
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@ -363,7 +347,6 @@ library interface.
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A more interesting example is in the examples/python/in.python script
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which loads and runs the following function from examples/python/funcs.py:
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.. code-block:: python
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def loop(N,cut0,thresh,lmpptr):
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@ -387,7 +370,6 @@ which loads and runs the following function from examples/python/funcs.py:
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with these input script commands:
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.. parsed-literal::
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python loop input 4 10 1.0 -4.0 SELF format iffp file funcs.py
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@ -440,10 +422,8 @@ being attempted.
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The same applies to Python functions called during a simulation run at
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each time step using :doc:`fix python/invoke <fix_python_invoke>`.
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----------
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If you run Python code directly on your workstation, either
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interactively or by using Python to launch a Python script stored in a
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file, and your code has an error, you will typically see informative
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@ -456,7 +436,6 @@ logic errors, you may get an error from Python pointing to the
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offending line, or you may get one of these generic errors from
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LAMMPS:
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.. parsed-literal::
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Could not process Python file
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@ -465,7 +444,6 @@ LAMMPS:
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When the Python function is invoked, if it does not return properly,
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you will typically get this generic error from LAMMPS:
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.. parsed-literal::
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Python function evaluation failed
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@ -485,7 +463,6 @@ Third, use Python exception handling. For example, say this statement
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in your Python function is failing, because you have not initialized the
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variable foo:
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.. code-block:: python
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foo += 1
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@ -493,7 +470,6 @@ variable foo:
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If you put one (or more) statements inside a "try" statement,
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like this:
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.. code-block:: python
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import exceptions
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@ -505,7 +481,6 @@ like this:
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then you will get this message printed to the screen:
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.. parsed-literal::
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FOO error: local variable 'foo' referenced before assignment
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@ -514,14 +489,11 @@ If there is no error in the try statements, then nothing is printed.
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Either way the function continues on (unless you put a return or
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sys.exit() in the except clause).
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----------
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Restrictions
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""""""""""""
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This command is part of the PYTHON package. It is only enabled if
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LAMMPS was built with that package. See the :doc:`Build package <Build_package>` doc page for more info.
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