top-down subgraphs, left-right inside subgraphs

Question

I'd like to have my graph looks like this:

But I can only get this:

The problem is, rankdir does not work in subgraph. So, how to emulate it?

The code:

digraph G {     node [shape = circle]     0 [style = invis]      0 -> "0A"      subgraph clusterA {         label=A         "0A"         "1A"         "2A" -> "0A" [label=•]     }      subgraph clusterB {         label=B         "0B"         "1B"         "2B" -> "0B" [label=•]     }          subgraph clusterC {         label=C         "0C"         "1C"         "2C" -> "0C" [label=•]     }      subgraph clusterD {         label=D         "0D"         "1D"         "2D" -> "0D" [label=•]     }      subgraph clusterE {         label=E         "0E"         "1E"         "2E" -> "0E" [label=•]     }      subgraph clusterF {         label=F             {node [shape = doublecircle] "0F" "1F"}         "2F" -> "0F" [label=•]     }      "0A" -> "1B" [label=a]     "1A" -> "2B" [label=a]     "0B" -> "1C" [label=b]     "1B" -> "2C" [label=b]     "0C" -> "1D" [label=c]     "1C" -> "2D" [label=c]     "0D" -> "1E" [label=d]     "1D" -> "2E" [label=d]     "0E" -> "1F" [label=e]     "1E" -> "2F" [label=e] } 

Answer 1

Reproducing particular graph layouts usually can be achieved with:

• Invisible nodes and edges
• rank constraints

Here's how I reproduced your graph - or at least a part of it:

digraph g {     rankdir="LR";     node[shape = circle, fontsize=14];     fontsize=18;     labeljust="l";      edge[style=invis, fontsize=12];      { rank=same;         0 [style = invis];         01 [style = invis];         02 [style=invis];         0 -> 01 -> 02;     }      subgraph clusterA {         "0A" -> "1A" -> "2A";         "2A" -> "0A" [label=".", constraint=false, style=solid];         label="A";     }      subgraph clusterB {         "0B" -> "1B" -> "2B";         "2B" -> "0B" [label=".", constraint=false, style=solid];         label="B";     }      subgraph clusterC {         "0C" -> "1C" -> "2C";         "2C" -> "0C" [label=".", constraint=false, style=solid];         label="C";     }      0 -> "0A"[style=solid];     01 -> "0B"[style=invis];     02 -> "0C"[style=invis];      // edges between clusters     edge[constraint=false, style=solid];     "0A" -> "1B" [label=a]     "1A" -> "2B" [label=a]     "0B" -> "1C" [label=b]     "1B" -> "2C" [label=b] } 

This solution is not very intuitive. A couple of points to achieve this:

• I chose rankdir="LR" which resulted in nicer edges than TB, though it does not really correspond with the direction of the graph
• Invisible nodes and edges are use for the top rank nodes (0, 01, 02) in order to have the clusters align left.
• The (invisible) top nodes are forced to the same rank and are linked by invisible edges - this will ensure that the clusters linked to each node appear in the correct order.

The result is: