title: Fast Interactive force-directed graph layout engine
body: <p>I need a framework/library which will enable me to develop a realtime interactive graph simulation. The user must be able to dynamically add nodes and edges. I have found <a href="http://prefuse.org/" rel="noreferrer">Prefuse</a> and its force directed layout and I really like it. But it is not fully thread-safe, and doesn't perform all that well -- maybe it has problems with big graphs?</p>
  
  <p>Are there some decent alternatives? I know about <a href="http://flare.prefuse.org/" rel="noreferrer">Flare</a>, but I have no desire to learn ActionScript and would rather stick with c++/java/c#.</p>