I have made a major change to the Vec and Mat internal data structures. PetscMap() is NO LONGER a PETSc object, it is now a simply data structure in the Vec and Mat objects. The m,M,n,N, rowners,rstart,rend, cstart and cstart fields in the Vec and Mat objects are removed, instead the fields in the map data structure inside the Mat and Vec are used. Aside from the missing PetscMap, this has not introduced any API interfaces. Making this change, almost for sure, introduced some errors (making the substantial code changes was painful and prone to error). Please track down the problems or let me know about them so we can eliminate the introduced problems. The external matrix packages have NOT been tested (they will be tested in nightly builds). Thus, if you are trying to get work done, instead of tracking down our bugs, I recommend not pulling petsc-dev for several days. Thanks for all your patience, Barry Yes, these code cleanups are painful, but they are also crucial to the long-term viability of PETSc.