[Nauty-list] plantri 64 vertex limit
Brendan McKay
bdm at cs.anu.edu.au
Sat May 16 15:50:21 EST 2009
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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