Provided by: nauty_2.6r10+ds-1_amd64 

NAME
nauty-twohamg - split quartic graphs into two hamiltonian cycles
SYNOPSIS
twohamg [-sgvq] [-L#] [infile [outfile]]
DESCRIPTION
Partition quartic graphs into two hamiltonian cycles.
Output those which cannot be partitioned.
-s force output to sparse6 format
-g 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.
-p Read a cubic graph and use its prism. Vertex i of the input becomes
vertices 2*i,2*i+1 in the prism.
-x Test for decompositions using each 2-path
-X As -x but only output if two 2-paths are missed at some vertex
-y 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 #
-Y With -p, only consider paths whose central edge is vertical
-v 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.
-q suppress auxiliary information
nauty 2.6.10 November 2017 NAUTY-TWOHAMG(1)