[petsc-users] DMDA Global vs Local indexing

[Mark Lohry]

I'm using DMDAs for managing my DOF data on structured grids, so 
processes have access to local array chunks from i=gxs; i<gxs+gxm. I 
have a lot of local/temporary data that I don't want PETSc to manage and 
I'm trying to keep PETSc as segregated from the rest of code as 
possible, so I'd prefer for any functions to be ignorant of particular 
ordering, and just access from i=0; i<gxm so that I'm using 0-indexed 
arrays locally. What's the appropriate way to go about doing this / 
getting direct access to the beginning of global-indexed local array?