firedrakeproject/firedrake — pull request #158 by wence- (2014-01-29 11:52:47+00:00)
Title: Use new inc_local_diagonal_entries to set bc nodes in Matrix

In parallel, we can't use zero_rows since the row indices are sent
through a map. Instead, given that we only actually need to set a value
on the diagonal, use new PyOP2 functionality to do that.