A selection of ill conditioned matrices.
Examples B and C are nearly diagonal (they must be at least order 4 and 3,
respectively). The parameter Theta is a linear contribution to elements
in Example B, and appears as 1/Theta and 1/Theta^2 in Example C.
Example D is a lower triangular matrix with 1's on the diagonal and -1's on the
off-diagonals; it depends only on the Order.
These matrices provide `counter-examples' to the LINPACK
condition number estimator.