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Create local repository for matrix toolboxes. Step #0 done.
author Antonio Pino Robles <data.script93@gmail.com>
date Wed, 06 May 2015 14:56:53 +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 [m, s, k] = quasitriang_struct(R)
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2 %QUASITRIANG_STRUCT Block structure of upper quasitriangular matrix.
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3 % [M,S,K] = QUASITRIANG_STRUCT(R), where R is an upper
8f23314345f4 Create local repository for matrix toolboxes. Step #0 done.
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4 % quasitriangular matrix, determines that R has M diagonal blocks,
8f23314345f4 Create local repository for matrix toolboxes. Step #0 done.
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5 % the i'th of which has order S(i) and starting position K(i).
8f23314345f4 Create local repository for matrix toolboxes. Step #0 done.
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6 % Any subdiagonal elements less than the tolerance EPS*NORM(R,'FRO')
8f23314345f4 Create local repository for matrix toolboxes. Step #0 done.
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7 % are treated as zero.
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8
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9 n = length(R);
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10 tol = eps*norm(R,'fro');
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11
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12 i = 1; j = 1;
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13
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14 while i < n
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15 k(j) = i;
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16 if abs(R(i+1,i)) <= tol
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17 s(j) = 1;
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18 else
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19 s(j) = 2;
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20 end
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21 i = i + s(j);
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22 j = j+1;
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23 end
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24
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25 if i == n
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26 k(j) = n;
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27 s(j) = 1;
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28 m = j;
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29 else
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30 m = j-1;
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31 end