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annotate minors.m @ 1031:2ef20d00b386 feature/advectionRV

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For easier comparison, return both the first order and residual viscosity when evaluating the residual. Add the first order and residual viscosity to the state of the RungekuttaRV time steppers
author Vidar Stiernström <vidar.stiernstrom@it.uu.se>
date Thu, 17 Jan 2019 10:25:06 +0100
parents eaf557023fbe
children
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eaf557023fbe Added verbose flag to semiDefIneq and minors.
Jonatan Werpers <jonatan@werpers.com>
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1 function [minor, sub] = minors(A, verbose)
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2 default_arg('verbose', true);
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0a881a3dc9a9 Cleaned up the code for minors.
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3 [n, m] = size(A);
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4
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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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8
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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
967152d7d58b Added function for printing the minors of a matrix.
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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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34