Mercurial > repos > public > sbplib
view minors.m @ 1037:2d7ba44340d0 feature/burgers1d
Pass scheme specific parameters as cell array. This will enabale constructDiffOps to be more general. In addition, allow for schemes returning function handles as diffOps, which is currently how non-linear schemes such as Burgers1d are implemented.
author | Vidar Stiernström <vidar.stiernstrom@it.uu.se> |
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date | Fri, 18 Jan 2019 09:02:02 +0100 |
parents | eaf557023fbe |
children |
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function [minor, sub] = minors(A, verbose) default_arg('verbose', true); [n, m] = size(A); if n ~= m error('A must be square'); end sub = {}; ks = {}; ind = 1:n; for k = 1:n C = nchoosek(ind,k); for i = 1:size(C,1) ks{end + 1} = k; sub{end + 1} = A(C(i,:),C(i,:)); end end for i = 1:length(sub) if verbose fprintf('%d:\n', ks{i}); disp(sub{i}) end minor(i) = det(sub{i}); end end % A is positive semidefinite if all minors are non-negative % A is negative semidefinite if all odd minors are non-positive and all even minors are non-negative