1) Can we move the section data structures from vecimpl.h to isimpl.h? in preparation for its refactoring and why is PetscSectionCreate in section.c defined in src/vec/vec/impls/seq? Can vsection.c be split in two with the only the "Vec" related routines kept in the Vec directory? 2) matimpl.h really needs vecimpl.h? #define __MATIMPL_H #include <petscmat.h> #include <petsc-private/petscimpl.h> #include <petsc-private/vecimpl.h> Doesn't seem to so I've removed the vecimpl.h and pushed Seems there may be a few of these unneeded dependencies hanging around, I'll try to hunt them down. Barry