Python Interface

Python Interface — Interface to the Python programming language

Description

The Python interface provides a link to the Python programming language, allowing GMAT to run Python functions as if they were native functions in the GMAT script language.

The interface cannot be controlled directly through the script language. Instead, GMAT starts the Python interface automatically when it calls a Python function.

The Python interface is accessed using GMAT's CallPythonFunction command. For details on calling a function and passing data, see the CallPythonFunction reference.

GUI

The Python interface in GMAT is launched and driven internally. Users do not have direct access to the interface from the GMAT graphical user interface.

Remarks

Interface Setup

The following conditions must be true for GMAT to successfully initiate communication with Python. All conditions must be true for the same instance of Python.

A compatible version of Python must be installed on the same machine on which GMAT is running. GMAT is built and tested with the latest version of 64-bit python avialable during final GMAT release preparation unless Python is released during the last few weeks of a GMAT release. The interface is linked with the Python binary libraries, so the installed version of Python on the user's machine must match the architecture and release used to build GMAT.
The architecture (32-bit or 64-bit) of GMAT and the installed version of Python must match. For example, the 32-bit version of GMAT is compatible only with the 32-bit version of Python.
The Python system accesses Python modules on the user's machine. This functionality is configured, including path information used by Python, by installing Python as a resource for all users of the machine.
On Windows:
- The following path entries (where Python is the path to the installed version of Python) must be present in the Path environment variable.
  
  Python
  
  Python/Scripts

On Linux:

The Python release used in the GMAT build must be the default Python package (that is, Python 3.4) accessed from the terminal.

Note

Common troubleshooting tips on Windows:

If you are using the officially-released 32-bit version of GMAT, make sure you have the 32-bit version of Python installed.

If the path above exists in your system Path variable, try placing it at the front of the path specification.

Python Engine Connection

Warning

GMAT does not close the Python interface after a run has completed. This feature prevents anomalous behavior that can occur when loading some Python modules repeatedly during a run, but it can lead to confusing behavior if Python files are changed and rerun in the same GMAT session.

We recommend restarting GMAT after editing Python functions in order to guarantee that your edits take effect when you rerun your script.

When GMAT runs a mission that contains a Python function call, it loads Python into memory as an embedded system in GMAT before it makes the function call. It then reuses this system for the rest of the GMAT session.

Python Interface

General Mission Analysis Tool