nautytwohamg(1)
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 2path
 X

As x but only output if two 2paths are missed at some vertex
 y

Test for decompositions using each nontriangular 3path

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 2paths.

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

 Graphs that time out are written to the output.
 q

suppress auxiliary information