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annotate minors.m @ 129:0a881a3dc9a9

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Cleaned up the code for minors.
author Jonatan Werpers <jonatan@werpers.com>
date Wed, 03 Feb 2016 17:41:46 +0100
parents minorsSym.m@967152d7d58b
children eaf557023fbe
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1 function [minor, sub] = minors(A)
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2 [n, m] = size(A);
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4 if n ~= m
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5 error('A must be square');
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6 end
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8 sub = {};
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9 ks = {};
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10
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11 ind = 1:n;
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12 for k = 1:n
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13 C = nchoosek(ind,k);
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14 for i = 1:size(C,1)
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15 ks{end + 1} = k;
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16 sub{end + 1} = A(C(i,:),C(i,:));
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17 end
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18 end
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20 for i = 1:length(sub)
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21 fprintf('%d:\n', ks{i});
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22 disp(sub{i})
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24 minor(i) = det(sub{i});
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25 end
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26 end
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29 % A is positive semidefinite if all minors are non-negative
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30 % A is negative semidefinite if all odd minors are non-positive and all even minors are non-negative
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