Mercurial > matrix-functions
comparison toolbox/vand.m @ 0:8f23314345f4 draft
Create local repository for matrix toolboxes. Step #0 done.
| author | Antonio Pino Robles <data.script93@gmail.com> |
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| date | Wed, 06 May 2015 14:56:53 +0200 |
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| -1:000000000000 | 0:8f23314345f4 |
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| 1 function V = vand(m, p) | |
| 2 %VAND Vandermonde matrix. | |
| 3 % V = VAND(P), where P is a vector, produces the (primal) | |
| 4 % Vandermonde matrix based on the points P, i.e. V(i,j) = P(j)^(i-1). | |
| 5 % VAND(M,P) is a rectangular version of VAND(P) with M rows. | |
| 6 % Special case: If P is a scalar then P equally spaced points on [0,1] | |
| 7 % are used. | |
| 8 | |
| 9 % Reference: | |
| 10 % N.J. Higham, Stability analysis of algorithms for solving | |
| 11 % confluent Vandermonde-like systems, SIAM J. Matrix Anal. Appl., | |
| 12 % 11 (1990), pp. 23-41. | |
| 13 | |
| 14 if nargin == 1, p = m; end | |
| 15 n = max(size(p)); | |
| 16 | |
| 17 % Handle scalar p. | |
| 18 if n == 1 | |
| 19 n = p; | |
| 20 p = seqa(0,1,n); | |
| 21 end | |
| 22 | |
| 23 if nargin == 1, m = n; end | |
| 24 | |
| 25 p = p(:).'; % Ensure p is a row vector. | |
| 26 V = ones(m,n); | |
| 27 for i=2:m | |
| 28 V(i,:) = p.*V(i-1,:); | |
| 29 end |