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	<title>Real-Time Physics Simulation Forum</title>
	
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	<updated>2014-11-22T13:54:29+00:00</updated>

	<author><name><![CDATA[Real-Time Physics Simulation Forum]]></name></author>
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		<entry>
		<author><name><![CDATA[bofjas]]></name></author>
		<updated>2014-11-22T13:54:29+00:00</updated>

		<published>2014-11-22T13:54:29+00:00</published>
		<id>https://pybullet.org/Bullet/phpBB3/viewtopic.php?p=34482#p34482</id>
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		<title type="html"><![CDATA[Coefficient matrix and convergence]]></title>

		
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I currently working on a 3d physics engine solver. The result from my collision detection is a set of contact points. A contact point consist of a point, a normal vector and two tangent vectors (for friction). I create a coefficient matrix for the entire system of bodies by splitting each contact point into 3 rows, one for the normal and one for each tangent. Any force interacting with a body will get non-zero values in the coefficient matrix for any constraint row on that body.<br><br>I created a general Jacobi iterative matrix solver to solve this linear system, but as my unit tests prove, certain matrices will not converge even though they have valid solutions. I researched online and learned that the Jacobi method is only guaranteed to converge when the coefficient matrix is diagonally dominant.<br><br>So my question is this: Is the coefficient matrix guaranteed to be diagonally dominant when generated from contact points?<p>Statistics: Posted by <a href="https://pybullet.org/Bullet/phpBB3/memberlist.php?mode=viewprofile&amp;u=11098">bofjas</a> — Sat Nov 22, 2014 1:54 pm</p><hr />
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