Re: [graphviz-interest] A problem with rank = same

> Is that a bug in Graphviz or have I misunderstood something? 
It is a bug, but not the one you think. The original ranking algorithm used in dot was especially 
cautious. In particular,
a node could not be involved in two constraints, a constraint being containment in a cluster or 
involvement in a rank=...
So what you are seeing is dot quietly ignoring the rank=same constraint because node_2 and node_3 
are in a cluster.
The bug is that dot should produce a warning about this.

This approach seemed too cautious, as it prohibited many perfectly reasonable situations as, for 
example, in your graph.

Since 2.30, dot supports a new ranking algorithm that is much more flexible. At present, it is still 
not the default, so you
need to set newrank=true to get it. If you do this, you'll see node_2 and node_3 in the cluster and 
on the same rank.

For the record, if you comment out "subgraph" but leave in "cluster", cluster denotes a node and you 
end up with an
edge from node_1 to cluster.

     Emden

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