[petsc-dev] status of MatBlock vs MatNest?

[Barry Smith]

   Is MatBlock needed now that MatNest exists?  Is MatBlock different enough 
that it is needed in addition to MatNest?

   MatBlock seems to support sparse matrices each entry of which is a sparse 
matrix with many rows and columns of blocks, is MatNest restricted to a smaller 
number of blocks?

   Is MatBlock working and tested?

   Thanks

    Barry