# Specific functions

## Introduction

This section describes the functions Modulo, Valid, Trapez, Trapezper and a function of substitution.

These functions are used in formulas with I/O parameters (for the transient applications or parameterized analysis). These functions can be also used in other formulas (arithmetic expression in the geometry context, …)

In case of transient applications, these functions allow to define signals with various form: periodic, pulse, trapezoidal, ...