Petsc Petsc is a package for the solution of PDE problems. It contains everything from linear algebra tools, through linear solvers, nonlinear solvers, and time-stepping methods. Since it is written in an object-oriented style, all data structures are hidden from the user. A large number of construction and inspection routines give access to the numerical data and parameters of the objects.
Petsc can use the preconditioners of the BlockSolve package; section 3.2.