title: graphviz - fixed node positions
body: <p>I have a graph that is processed by neato and I'm adding new edges to it. However, I don't want that the old nodes to be moved. I want that neato computes the new positions of the new nodes and the old nodes stay in the same place.</p>
  
  <pre><code>strict graph {
      node0 [pos="1,2"];
      node1 [pos="2,3"];
  }
  </code></pre>
  
  <p>and I add new edges:</p>
  
  <pre><code>strict graph {
      node0 [pos="1,2"];
      node1 [pos="2,3"];
      node1 -- node2 [len="3"];
      ...
  }
  </code></pre>
  
  <p>I want to get the same positions on the old nodes. For example:</p>
  
  <pre><code>strict graph {
      node0 [pos="1,2"];
      node1 [pos="2,3"];
      node2 [pos="3,4"];
      ...
  }
  </code></pre>
  
  <p>How can I do that?</p>