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annotate minors.m @ 1198:2924b3a9b921 feature/d2_compatible

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Add OpSet for fully compatible D2Variable, created from regular D2Variable by replacing d1 by first row of D1. Formal reduction by one order of accuracy at the boundary point.
author Martin Almquist <malmquist@stanford.edu>
date Fri, 16 Aug 2019 14:30:28 -0700
parents eaf557023fbe
children
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eaf557023fbe Added verbose flag to semiDefIneq and minors.
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1 function [minor, sub] = minors(A, verbose)
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2 default_arg('verbose', true);
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3 [n, m] = size(A);
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5 if n ~= m
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6 error('A must be square');
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7 end
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9 sub = {};
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10 ks = {};
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11
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12 ind = 1:n;
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13 for k = 1:n
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14 C = nchoosek(ind,k);
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15 for i = 1:size(C,1)
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16 ks{end + 1} = k;
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17 sub{end + 1} = A(C(i,:),C(i,:));
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18 end
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19 end
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20
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21 for i = 1:length(sub)
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22 if verbose
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23 fprintf('%d:\n', ks{i});
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24 disp(sub{i})
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25 end
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27 minor(i) = det(sub{i});
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28 end
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29 end
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32 % A is positive semidefinite if all minors are non-negative
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33 % A is negative semidefinite if all odd minors are non-positive and all even minors are non-negative
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