#### Description

The `Dorr' matrix is
A diagonally dominant, tridiagonal,
M-matrix.
It is ill conditioned
for small values of the (positive) parameter, theta.
The columns of the inverse of this matrix vary greatly in norm.
The first and last elements are row-diagonally dominant where
The amount of diagonal dominance is given by (ignoring rounding errors):

|A_{1,1}|-|A_{1,2}| = THETA*(N+1)^2
|A_{N,N}|-|A_{N,N-1}| = THETA*(N+1)^2

#### References

- This generator is adapted from Nicholas J. Higham's
Test Matrix Toolbox.
- F.W. Dorr, An example of ill-conditioning in the numerical
solution of singular perturbation problems, Math. Comp., 25 (1971),
pp. 271-283.

The Matrix Market is a service of the
Mathematical and Computational Sciences Division /
Information Technology Laboratory /
National Institute of Standards and Technology

[ MatrixMarket Home ]
[ MatrixMarket Deli Home ]
[ Search ]
[ Browse ]
[ Resources ]

Page created 1997-03-03, last modified 2000-08-06.
[
]