[petsc-users] amg from hypre

[hxie at umn.edu]

Hi,

I am solving incompressible navier-stokes equations. The code implements 
the Newton iteration and just uses the KSP solver for each iteration. It 
takes 14 nonlinear iterations (~8min) to converge using the default solver 
in PETSc. But it takes 6 nonlinear iterations (~30min) using boomeramg from 
hypre. The amg taks less iterations but takes too much cputime. Is this 
normal? One friend told me the reason may be that I did not call the 
destroy function to free the memory in each Newton iteration (I called 
PetscFinalize after all the Newton iterations). How can I call the 
PCDestroy_HYPRE from a fortran code? Will there be significant difference 
in cputime to call amg directly from hypre? Thanks for any help.

Bests,
Hui