  We give an introduction to the Mathematica packages "MasterPVA" and
"MasterPVAmulti used to compute lambda-brackets in Poisson vertex algebras,
which play an important role in the theory of infinite-dimensional Hamiltonian
systems. As an application, we give an introduction to the Mathematica package
"WAlg" aimed to compute the lambda-brackets among the generators of classical
affine W-algebras. The use of these packages is shown by providing some
explicit examples.
