# Global solver

${\rm I\!R}^p$ spaces have no ordering relations when $p$ is greater than 1. As a consequence, 
finding the minimum of a function the output of which is defined in such a space has no meaning. 
Multicriteria optimisation solves this problem by finding the inputs corresponding to the *Pareto 
frontier* in the costs space.

The evolutionary algorithm library **Vizir**, allows to perform multicriteria optimisation with a 
global approach, and is available in {{uranie}}. It is first introduced in a broad picture (even 
though more details can be found in {{metho}}) before considering the different solvers available 
and their possible configuration. We have also illustrate its use in a simple example that can be 
found in [](#use_cases_macro_reoptimizer_bar_code_vizir).

```{toctree}
global_solver/vizir
global_solver/tvizir2_tvizirisland
global_solver/solvers
```