# wilkinson

## Purpose

Wilkinson's eigenvalue test matrix.

## Synopsis

    W = wilkinson(n)

## Description

`wilkinson(n)` is one of J. H. Wilkinson's eigenvalue test matrices. It is a symmetric, tridiagonal matrix with pairs of nearly, but not exactly, equal eigenvalues.

## Examples

`wilkinson(7)` is

        3    1    0    0    0    0    0
        1    2    1    0    0    0    0
        0    1    1    1    0    0    0
        0    0    1    0    1    0    0
        0    0    0    1    1    1    0
        0    0    0    0    1    2    1
        0    0    0    0    0    1    3

The most frequently used case is `wilkinson(21)`. Its two largest eigenvalues are both about 10.746; they agree to 14, but not to 15, decimal places.

## See Also

    eig, pascal, rosser

(c) Copyright 1994 by The MathWorks, Inc.