QPFit/sample_polytope.m
3bfb25b5e70amaster

sample_polytope.m
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			function X = sample_polytope(P, N, tol)
			%
			% Extract N samples uniformly from the polytope P
			%

			cheb = P.chebyCenter;
			if nargin > 2
			if cheb.r < tol
			X = [];
			return
			end
			end

			A = P.A; b = P.b;

			% clf
			% plot(P,'wire', true)
			% hold on

			X = zeros(P.Dim, N);
			dir = 2*rand(P.Dim,1) - 1; dir = dir / norm(dir);
			X(:,1) = cheb.x + dir * cheb.r * rand;
			spoke = false;
			tic
			for i = 2:N
			if toc > 2
			fprintf('Generated %i samples of %i\n', i, N);
			spoke = true;
			tic
			end

			x = X(:,i-1);

			dir = 2*rand(P.Dim,1)-1;
			% dir = randn(P.Dim,1);
			red = (b - Ax) ./ (Adir);
			red(red < 0) = [];
			gamma = min(red);

			xp = x + dir*gamma;
			X(:,i) = x + randgammadir;

			% plot(x(1), x(2), 'o');
			% h = plot([x(1);xp(1)], [x(2);xp(2)], '-o');
			% pause(0.1)
			% drawnow
			% delete(h)
			end

			if spoke
			fprintf('Generated %i samples of %i\n', i, N);
			end