# Geometric parameter: definition (structure)

## Definition

A geometric parameter is defined by:

- a name (and a comment)
- an algebraic expression

## Name

The name to identify the geometric parameter is set by the user during the creation of this one.

A comment (optional) can be added to the name.

## Algebraic expression

The algebraic expression can contain:

- constants
- geometric parameters (created beforehand)
- basic mathematical functions using operators: +, -, *, /, ( )
- usual mathematical functions admitted by FORTRAN

The mathematical functions are described in section Functions.