# PythonΒΆ

Type: | section |
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Appearance: | simple |

Excludes: | OutputQuantity |

This section is used to define a flux density expression by means of a Python script. `JCMsuite`

comes with a Python interpreter, therefore an installation of Python is not required.

Note

Since Version 6.2.0 `JCMsuite`

uses Python 3.10 as available from http://www.python.org. It further includes the `NumPy`

-package, see http://www.scipy.org.

The Python script based integrand definition is very flexible and general, since it is possible to define parameter-dependent expressions. These parameters may not only contain user-defined fixed values, but may also describe dependencies on tensor fields. Furthermore, it offers a simple way to compute mutual overlap integrals.

To explain this in more detail, let us denote the flux density - tensor field we want to define by where is the position vector and is the time. The flux density - tensor field which may depend on the values of other tensor fields at the same position is described as:

The Python script is provided by the user. There are two options to do this:

- Inline definition of a python expression directly within the post-process file, see section Expression.
- Reference to a function contained in a python module, see section Function.

The argument values as well as the positions should be passed from `JCMsolve`

to the python script when evaluating the flux density field. For being able to do this, the user has to inform `JCMsolve`

which parameters are actually needed. In the words of a computer programming language the user has to specify the *signature* of the python script. This is done by filling the Parameter section.

`JCMsolve`

computes the integral values for each physical domain separately ( is the domain index):

A tensor field parameter is ambiguous when imported from a JCM fieldbag which contains more than one field of the desired type. In this case, `JCMsolve`

should compute the integral values for each field separately. This necessitates an additional integral index.

More generally, we allow for more than one integral indices to compute mutual overlap integrals. For each tensor field parameter one specifies which integral index runs with the field index:

Here, the super indices and denote the field index of the tensor field parameters. In the above, the field index of the first tensor field parameter runs with the first integral index , whereas the field index of runs with the second index .