The use of simulation methods in the design of electronic systems is often an important part of the production process. Modeling allows indeed to analyze circuits and optimize without having to manufacture them actually. The result is a much higher production speed and lower cost. In many cases, the system to be modeled is translated as solving a system of linear equations on the basis of an iterative process; the computational time required to obtain a direct solution is much too high by inverting the system matrix. But even with this solution method, the simulation time should drop many orders of magnitude to be practical.