Matrix Market Deli
Test matrices made to order ... while you wait
Each generator is assembled into an application
these generators can probably only be used with relatively recent browsers
(eg. Netscape or Internet Explorer versions 4 or above).
most of the generators presented here are adapted from
Nicholas J. Higham's worthwhile
However Test Matrix Toolbox.
tridiagaonal, square matrix with zero diagonal;
has explicitly known inverse, eigenvalues
and eigenvectors; may be symmetric,
Condition Estimate Counterexample A set of
ill conditioned matrices
which are counter examples to the LINPACK
condition number estimator.
Cyclic Column A matrix with random cyclic columns;
For some values of parameters, it may be
symmetric, square, Hankel matrix
whose eigenvalues cluster around ±PI/2.
diagonally dominant, tridiagonal,
possibly ill conditioned
for small values of the parameter.
Forsythe A perturbed
Jordan Block matrix.
Frank An upper
with ill conditioned
eigenvalues, whose determinant is 1.
Gear A sinple
singular matrix with known
eigenvalues; can be rank deficient,
and can have double and triple eigenvalues.
symmetric, positive definite,
totally positive, Hankel matrix;
a famous badly conditioned matrix; inverse is known explicitly.
Jordan Block, matrix;
it is defective with known eigenvalue.
Kahan An upper trapezoidal matrix that has some
interesting properties regarding estimation of condition and rank.
Lauchli A rectangular matrix; a well known example from least squares indicating
the dangers of A
Lotkin An unsymmetric,
totally positive, and has many small, negative eigenvalues;
inverse has integer entries and is known explicitly.
Random Random sparse matrices of arbitrary size and density.
Wilkinson A matrix for which Gaussian elimination with partial pivoting yields
a large growth factor.
The Matrix Market is a service of the
Mathematical and Computational Sciences Division /
Information Technology Laboratory /
National Institute of Standards and Technology
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Page created 1997-03-03, last modified 2002-04-10.
matrixmarket @ nist.gov