The Hybrid Identification Toolbox (HIT) is a free MatLab toolbox, developed by Giancarlo Ferrari-Trecate, for regression with PieceWise Affine (PWA) maps and identication of PieceWise AutoRegressive eXogenous (PWARX) models. A key feature of HIT is the capability of reconstructing discontinuous models. HIT provides facilities for plotting and validating the identified models.

It is a tool, developed by INRIA, that:

• Replicates in silico the dynamics of genetic interaction networks.
• Supports the construction and simulation of dynamic models expressed in a powerful formalism specifically designed to fit the level of biological data availability.

The behaviours generated by the simulation of the models can be compared with experimental expression data.