Correction of the initial conditions

"Series title: Springerbriefs in applied sciences and technology, ISSN 2191-530X"

This chapter presents a general approach to deal with the correction of the initial conditions at the position and velocity levels. This procedure is of paramount importance to avoid constraints violation during the numerical resolution of the equations of motion. The material presented here closely follows the standard methodologies available in the literature. Thus, in this chapter, a simple and efficient approach to correct the initial conditions at the position and velocity levels is revised.