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author Antonio Pino Robles <data.script93@gmail.com>
date Fri, 29 May 2015 09:48:36 +0200
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8f23314345f4 Create local repository for matrix toolboxes. Step #0 done.
Antonio Pino Robles <data.script93@gmail.com>
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1 function A = cycol(n, k)
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2 %CYCOL Matrix whose columns repeat cyclically.
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3 % A = CYCOL([M N], K) is an M-by-N matrix of the form A = B(1:M,1:N)
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4 % where B = [C C C...] and C = RANDN(M, K). Thus A's columns repeat
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5 % cyclically, and A has rank at most K. K need not divide N.
8f23314345f4 Create local repository for matrix toolboxes. Step #0 done.
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6 % K defaults to ROUND(N/4).
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7 % CYCOL(N, K), where N is a scalar, is the same as CYCOL([N N], K).
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Antonio Pino Robles <data.script93@gmail.com>
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8 %
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9 % This type of matrix can lead to underflow problems for Gaussian
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10 % elimination: see NA Digest Volume 89, Issue 3 (January 22, 1989).
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12 m = n(1); % Parameter n specifies dimension: m-by-n.
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13 n = n(max(size(n)));
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15 if nargin < 2, k = max(round(n/4),1); end
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17 A = randn(m, k);
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18 for i=2:ceil(n/k)
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19 A = [A A(:,1:k)];
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20 end
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8f23314345f4 Create local repository for matrix toolboxes. Step #0 done.
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22 A = A(:, 1:n);