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comparison toolbox/pei.m @ 2:c124219d7bfa draft

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Re-add the 1995 toolbox after noticing the statement in the ~higham/mctoolbox/ webpage.
author Antonio Pino Robles <data.script93@gmail.com>
date Thu, 07 May 2015 18:36:24 +0200
parents 8f23314345f4
children
comparison
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1:e471a92d17be 2:c124219d7bfa
1 function P = pei(n, alpha)
2 %PEI Pei matrix.
3 % PEI(N, ALPHA), where ALPHA is a scalar, is the symmetric matrix
4 % ALPHA*EYE(N) + ONES(N).
5 % If ALPHA is omitted then ALPHA = 1 is used.
6 % The matrix is singular for ALPHA = 0, -N.
7
8 % Reference:
9 % M.L. Pei, A test matrix for inversion procedures,
10 % Comm. ACM, 5 (1962), p. 508.
11
12 if nargin == 1, alpha = 1; end
13
14 P = alpha*eye(n) + ones(n);