What is the function that solves the crossing number of graphs

[lc Z]

Dear OGDF team,

I see an example of mathoverflow from 10 years ago, which is to compute the cross number of the Grötzsch graph.

• cross number of the Grötzsch graph
  

Jamie J. Taylor said  in the answer that OGDF can be used. But I don't see the corresponding codes. 

He said: 

The crossing number of the Grötzsch graph is 5.

Crossing numbers are believed to be difficult to compute in general. (The corresponding decision problem is NP-hard.) However, for small graphs and small crossing numbers, it is possible to find an optimal planar drawing. For example, see Markus Chimani's thesis "Computing Crossing Numbers" for more information.

The Open Graph Drawing Framework (OGDF) can compute crossing numbers. After compiling the program on the linked page and entering the Grötzsch graph, my computer computed that the optimal planar drawing has 5 crossings. Let me emphasize that this technique is exact, not heuristic.

I would like to ask what the function is that solves the crossing number of graphs. At present, I am a C++ and OGDF beginner and have not fully understood. I'm so sorry to bother you.

Best wishes,

Licheng Zhang.

[Dagobert Smart]

Dear Licheng Zhang,

to my knowledge the code sadly does not exist in the OGDF release (anymore?). The mathoverflow answer is ten years old, so it's not surprising that it is not up-to-date on the current code of the OGDF.

For the exact computation of crossings numbers, I can only recommend crossings.uos.de (which was down for some time but is now up again).

Best regards,

Dagobert