  Some of the most interesting scenarios that can be studied in astrophysics,
contain fluids and plasma moving under the influence of strong gravitational
fields. To study these problems it is required to implement numerical
algorithms robust enough to deal with the equations describing such scenarios,
which usually involve hydrodynamical shocks. It is traditional that the first
problem a student willing to develop research in this area is to numerically
solve the one dimensional Riemann problem, both Newtonian and relativistic.
Even a more basic requirement is the construction of the exact solution to this
problem in order to verify that the numerical implementations are correct. We
describe in this paper the construction of the exact solution and a detailed
procedure of its implementation.
