[Nauty-list] plantri 64 vertex limit

[Brendan McKay]

plantri is for making exhaustive lists of graphs in specified
classes and even doing that for 30-vertex triangulations would be
a very major task. Moreover if you just run the generator for a
short time, the graphs you get out will be an extremely non-random
selection.  So I think plantri is not suitable for your application.

However, you can get plantri to make larger sizes by compiling with a
larger value of MAXN.  In Linux:   
    cc -o plantri -O3 -DMAXN=128 plantri.c
There are limits depending on the output format, see the source code.

If you want to mak reasonably random large triangulations, I suggest
you make any triangulatiuon at all, then flip diagonals at random a
large number of times.  Flipping a diagonal means to delete an
edge then insert the other diagonal of the resulting 4-cycle.

Brendan.

* Jim Beagle <beaglemaniaus at yahoo.com> [090516 10:46]:
> 
> Hello, I found showg in nauty to convert format to human readable form, so that problem is solved. 
> 
> But I still can't get a graph with more than 64 vertices, I need at least 100.
> 
> [george at alpha graphs]$ ./plantri -g  66 > out
> ./plantri -g 66 
> >E ./plantri: the value of n must be 4..64
> 
> 
> [george at alpha graphs]$ ./plantri -u  66 > out
> ./plantri -u 66 
> >E ./plantri: the value of n must be 4..64
> 
> Just downloaded plantri so it must be latest version.
>  
> Thanks
> 
> John
> 
> 
>       
> 
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