Garth is getting a segv when he uses -pc_gamg_asm_use_agg and an overlap of 1.
This seems like a pretty hard thing to do right and I would not be surprised if it was not done with complete generality. MatGetSubMatrix is find to get any submatrix but enlarging a remote subdomain seems very tricky. Should I perhaps check for overlap in GAMG and give an error? Maybe it would be better to have ASM do this. Maybe I could make ASM have a flag am-i-nested and not allow overlap if not? Mark
