nauty-twohamg man page

nauty-twohamg — split quartic graphs into two hamiltonian cycles


twohamg [-sgvq] [-L#] [infile [outfile]]


Partition quartic graphs into two hamiltonian cycles.

Output those which cannot be partitioned.

force output to sparse6 format

force output to graph6 format If neither -s or -g are given, the output format is determined by the header or, if there is none, by the format of the first input graph. Also see -S.

The output file will have a header if and only if the input file does.


Read a cubic graph and use its prism. Vertex i of the input becomes

vertices 2*i,2*i+1 in the prism.

Test for decompositions using each 2-path
As -x but only output if two 2-paths are missed at some vertex
Test for decompositions using each non-triangular 3-path

-t# With -x and -X, consider only paths with center #

With -y, consider only paths starting at #
With -p, only consider paths whose central edge is vertical
Give a partition for those graphs who have one and a message for those which don't. With -x, list exceptional 2-paths.

-L# Limit to 1000*# iterations; write with message if timeout.

Graphs that time out are written to the output.
suppress auxiliary information


nauty 2.6.7 September 2016