[petsc-users] Any Examples for 3D Poisson Solver with both Dirichlet and Neumann BC's

[Zhenglun (Alan) Wei]

Dear All,
     Any suggestions on a 3D Poisson Solver with both Dirichlet and 
Neumann BC's?
     Also, does PETSc have any example of Poisson solver (either 2D or 
3D) with periodic boundary conditions.

thanks
Zhenglun