[petsc-users] Providing Interpolation/Injections to Multigrid infrastructure

[Boris Boutkov]

Hello All,

I'm currently working on hooking into the PETSc multi-grid 
infrastructure by creating my own DMShell and providing my own 
interpolation and injection operators. The issue I am currently facing 
is that while PCSetUp_MG is running, PETSc begins by attempting to 
create an interpolation (through DMCreateInterpolation) for the finest 
grid that I am passing it.

What would be a good way to try and let the PCSetUp_MG procedure know 
the first mesh it is receiving is the finest one, so there should be no 
interpolation provided to it?

Thanks for your help,
Boris