.. _d7.01.03:

**d7.01.03** Develop a new option
=============================================

**Summary:**

This document complements the development training presentations.
It details the steps required to complete the addition exercise
of a new calculation option on a finite element.

It is proposed to create a new option that allows the calculation of the average stresses per cell.

To do this, the following steps will be followed:

- write a test case to test its development;
- add a "SIGM_ELEM" field in the "CALC_CHAMP" order catalog;
- add a new field "SIGM_ELEM" in the result data structure;
- define a new calculation option "SIGM_ELEM" with its input and output parameters;
- modify the finite element catalogs, local modes and parameters following the addition of this new option;
- calculate the average stress per element in a ``te``;
- build and test its development.


**Note:**

    The essential prerequisites before starting to develop is to know:

    - the Fortran,
    - Python (including Object Oriented Programming),
    - the Git version manager,
    - the GitLab interface.

    A skeleton of the necessary files is provided during the training in order to
    to guide new developers.

    It is recommended to start with :ref:`d7.01.01-build-ref`, then
    The :ref:`d7.01.01-build-branch`.


.. toctree::
    :hidden:

    self

.. toctree::
    :maxdepth: 2
    :numbered:

    objectif
    catalog
    sdresult
    options
    compute