Mercurial > matrix-functions
comparison toolbox/moler.m @ 2:c124219d7bfa draft
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
equal
deleted
inserted
replaced
1:e471a92d17be | 2:c124219d7bfa |
---|---|
1 function A = moler(n, alpha) | |
2 %MOLER Moler matrix - symmetric positive definite. | |
3 % A = MOLER(N, ALPHA) is the symmetric positive definite N-by-N matrix | |
4 % U'*U where U = TRIW(N, ALPHA). | |
5 % For ALPHA = -1 (the default) A(i,j) = MIN(i,j)-2, A(i,i) = i. | |
6 % A has one small eigenvalue. | |
7 | |
8 % Nash (1990) attributes the ALPHA = -1 matrix to Moler. | |
9 % | |
10 % Reference: | |
11 % J.C. Nash, Compact Numerical Methods for Computers: Linear | |
12 % Algebra and Function Minimisation, second edition, Adam Hilger, | |
13 % Bristol, 1990 (Appendix 1). | |
14 | |
15 if nargin == 1, alpha = -1; end | |
16 | |
17 A = triw(n, alpha)'*triw(n, alpha); |