Does the dot Directed Graph allow for subgraphs with a different rankdir?

Question

Using the dot directed graph language, is it possible to create subgraphs with a different rankdir?

I tried the following, which didn't work. Both graphs were left to right, despite the presence of rankdir="TB" in the subgraph.

digraph g {
    rankdir="LR";
    LEFT->RIGHT;
    clusterrank="local";

    subgraph cluster1 { 
        rankdir="TB";    
        node[style=filled];         
        color=black;
        TOP->BOTTOM;                
    }   
}

Is there some other syntax to get a Top/Bottom and Left/Right graph in the same diagram, or is this not possible?

Answer 1

Seems like this is a long standing feature request: http://www.graphviz.org/bugs/b1279.html

Answer 2

Desperately wanting the same feature, i Googled and there is a "trick": Essentially, you add invisible edges (and nodes if required) to sink the ranks.

Answer 3

There's a clusterrank attribute for subgraphs, try this:

clusterrank=local;