gusucode.com > elmat工具箱matlab源码程序 > elmat/private/ris.m
function A = ris(n,classname) %RIS Ris matrix (symmetric Hankel). % A = GALLERY('RIS',N) is a symmetric N-by-N Hankel matrix with % elements A(i,j) = 0.5/(N-i-j+1.5). % The eigenvalues of A cluster around PI/2 and -PI/2. % This matrix was invented by F. N. Ris. % Reference: % J. C. Nash, Compact Numerical Methods for Computers: Linear Algebra % and Function Minimisation, second edition, Adam Hilger, Bristol, % 1990 (Appendix 1). % % Nicholas J. Higham % Copyright 1984-2005 The MathWorks, Inc. p= -2*(1:n) + (n+1.5); A = gallery('cauchy',p,classname);