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