How to force all nodes in the same column in graphviz?

问题

I'm trying to model a certain flow using graphviz, and I can't figure out how to model the following graph to share the same horizontal center

digraph exmp {
   A -> B -> C -> D
   C -> E [constraint=false]
   A -> C [style="dotted", constraint=false]
   A -> D [style="dotted",  constraint=false]
   B -> D [constraint=false]
   D -> A [style="dashed", constraint=false]
   C -> A [style="dashed", constraint=false]


   subgraph cluster_hackToSinkIt { E -> F }
   { rank="sink" E F }
}

this results in the following graph:

My question is, how can I get the E -> F to be positioned under D such that is lies in the same column?

回答1:

At least as of May 2007, you can't force "columns" per se, but you can apply weight to edges which should help force alignment. But actually, in this case, if you just add an invisible edge from D to E, you've got vertical alignment.

digraph exmp {
    A -> B -> C -> D
    C -> E [constraint=false]
    A -> C [style="dotted", constraint=false]
    A -> D [style="dotted",  constraint=false]
    B -> D [constraint=false]
    D -> A [style="dashed", constraint=false]
    C -> A [style="dashed", constraint=false]
    D -> E [style="invis"] // <---- important new line


    subgraph cluster_hackToSinkIt { E -> F }
    { rank="sink" E F }
}

I'm not aware of any way to force edges to one side or another.

来源：https://stackoverflow.com/questions/1476241/how-to-force-all-nodes-in-the-same-column-in-graphviz