Dear firedrakers, we currently rely on petsc next, but you may have noticed, if installing petsc4py recently, that you can't build it with petsc next right now. Hopefully our dependencies will settle down a bit soon and you won't have to go through this upgrade dance. In the mean time, if you see a pip install petsc4py error like the below: src/petsc4py.PETSc.c:206419:43: error: ‘DMADDA’ undeclared (first use in this function) src/petsc4py.PETSc.c:206419:43: note: each undeclared identifier is reported only once for each function it appears in error: command '/usr/bin/mpicc' failed with exit status 1 Please do the following: $ git clone https://bitbucket.org/petsc/petsc4py Apply this patch: https://gist.github.com/wence-/11179460 and then in the petsc4py directory $ sudo python setup.py install (or no sudo if you haven't been using sudo to install things) Cheers, Lawrence