We can easily create the CSR and CSC constructors by using the
SparsityPattern constructors. However, one lingering problem
is giving meaningful error messages. When forwarding error messages
from the SparsityPattern constructor, the error messages must
be written in terms of "major" or "minor" dimensions, and using
general terms like "lanes", instead of "rows" and "columns".
When forwarding these messages up to CSR or CSC constructors,
they are not directly meaningful to an end user. We should find
a better solution to this problem, so that end users get
more meaningful messages.
