[Nauty-list] generating some graphs

[zstanic at matf.bg.ac.yu]

I am trying to generate some connected (3,4)-semiregular bipartite graphs
on 21 vertices and 36 edges. In this purpose I run the following command:

geng 21 -c -b 36:36 -d3 -D4 > out.txt

And everything is going fine until the moment when the program stops
writing the graphs into the output file but still running. In the first
two situations the program brokes in the same place. In that moment
out.txt had 848kb, and the last 5 lines of this file are:

T?????????W?k?[?@w?Po at k?Dg?SgF_??@J?
T?????????W?k?[?@w?Po at k?Dg?QgF_??AJ?
T?????????W?k?[?@w?Po at k?Dg?EgF_??GJ?
T?????????W?k?Y??{?M_ at k?@sE_O at oOBGG?
T?????????W?k?

In the third situation (on a different computer), the program brokes in a
different place. In that moment out.txt had 832kb, and the last 5 lines of
this file are:

T???????????{?b_?N?BgQQ?sC at d?AWGAAW?
T???????????{?b_?N?BgQQ?sCCT?AK_?oK?
T???????????{?b_?N?BgQQ?sCAT?Dc??C[?
T???????????{?b_?N?BgQQ?sCAT?@k?A?[?
T???????

In both casses, one graph is not completed. And in both cases I waited a
few hours to see if something changes, but the output was the same all
this time.

Note: I am using nauty 2.2.

Can somebody explain this?


Zoran Stanic,
University of Belgrade, Serbia