[Nauty] Nauty - revision 8 of version 2.6

Brendan McKay Brendan.McKay at anu.edu.au
Sun Aug 13 08:52:02 AEST 2017

Version 2.6r8 can be downloaded at


The differences from 2.6r7 are:
nauty.h: Fixed a typo:  HAVE_HWPOPCMT -> HAVE_HWPOPCNT
gentreeg.c:  Fixed output for 2 vertices, also used GENTREEG_MAIN properly
amtog.c:  Added option s for reading tournaments as upper triangles

If you are a tiny bit more adventurous (which I recommend) you can
download beta version 2.7b5 at


The differences from 2.6r6 to 2.7b5 are:
* -h and -k options for independent set size and clique size were added
   to countg and pickg.  For some graphs these use the program cliquer,
   kindly provided by Sampo Nisjkanen and Patric Ostergard.
* Macros SWHIBIT, REMOVEHIBIT and ATMOSTONEBIT added to nauty.h.
* Added option -a to complg.
* Program copyg can now be used to make a simple filter.  See the
   instructions inside the source file and the example numleaves.c.
* Programs countg and pickg can now display some parameter values
   as ranges instead of writing a separate line for each value. For
   example, countg --ne:T will write a separate line for each number
   of vertices and edges, with that line showing the range of the
   number of triangles. Everything after the ':' is shown as a range.
   There is also a switch -1 that causes output to be in a simple
   numerical table easy to read from a program.
* Program vcolg now handles digraphs and graphs with loops.
* genrang can now make random spanning trees of K(n1,n2)
* amtog has an "s" command for reading tournaments
* gentreeg made the same tree twice for n=2; thanks to Kevin Ryde
   for reporting it.

As always, all problem reports are welcome.


On 12/8/17 8:39 am, Brendan McKay wrote:
> Thanks Kevin,
> The GENTREEG_MAIN problem was reported by Saul Spatz a few months ago.
> The duplication for n=2 is more serious.  I'll fix this as soon as I 
> can and
> post a link to the corrected beta version when it is ready.
> Brendan.
> On 12/8/17 8:38 am, Kevin Ryde wrote:
>> In the debian i386 packaged nauty 2.6r7, running "nauty-gentreeg 2" 
>> prints
>>      >A nauty-gentreeg Z=1:1 D=1 n=2
>>      >Z 2 trees generated in 0.00 sec
>>      :An
>>      :An
>> where I thought preferably it shouldn't duplicate (for say consistency
>> of counts of trees, etc).
>> Nosing around the gentreeg.c code I noticed too GENTREEG_MAIN is used
>> for renaming main() for use in a program, but at the end there's a
>> #ifdef checking GENG_MAIN to do return vs exit.  Perhaps the latter
>> would be GENTREEG_MAIN too?
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