Finite-state machine model for natural language processing.  Roy Tromble.

A matrix from Roy Tromble
(royt :at the domain: cs.jhu.edu)
a PhD student in Computer Science
at Johns Hopkins University (in Jan 2003).  For this matrix, UMFPACK v4.0 and
v4.1 perform an unusually large number of symbolic defragmentations in the
ordering / analysis phase.

The matrix comes from finite-state machines for natural-language processing.
It has a zero-free diagonal, but a very unsymmetric nonzero pattern.
Factorizing A instead of A' may give better results.