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Wilkinson's eigenvalue test matrix
W = wilkinson(n)
W = wilkinson(n)
returns one of J. H. Wilkinson's eigenvalue test matrices. It is a symmetric, tridiagonal matrix with pairs of nearly, but not exactly, equal eigenvalues.
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.
eig Eigenvalues and eigenvectors
gallery Test matrices
pascal Pascal matrix