1. Introduction

For Code_Aster, a quantity is composed of an identifier (its name), a type and a list of components.

Example of size:

• DEPL_R: name of the magnitude of the real displacements at the nodes. This quantity is associated with the real type R and the components DX, DY, DZ, DRX, DRY, DRZ,…

In Code_Aster, a distinction is made between simple quantities and elementary quantities. The elementary quantities are attached to the elementary vectors or matrices. They are built from simple quantities. All these quantities (simple and elementary) are described in the Commons/physical_quantities.py file. The description of the elementary quantities is given in [§ 4]

We will try to answer the questions:

• what do I need to do to add a new size?

• what do you need to do to add a new component to an existing quantity?

• which catalogs need to be modified?

The introduction of a new magnitude requires two actions:

• the modification of the size catalog: physical_quantities.py,

• the modification of the order catalog: c_nom_size.capy

We will detail these two actions in succession.