xenial (1) nauty-watercluster2.1.gz

NAME

       nauty-watercluster2 - (faster alternative to directg)

SYNOPSIS

       watercluster2 [ix] [oy] [S] [T] [B] [C] [m]

DESCRIPTION

              Reads graphs in g6 code or multicode (optional) from stdin and directs them

              ix : the indegree of every vertex may be at most x.

              The default maximum indegree is unlimited.

              oy : the outdegree of every vertex may be at most y.

              The default maximum outdegree is unlimited.

              S : allow that for every pair of vertices x,y at most one of the edges x-->y

              and y-->x may be present. By default both of them may be present in the same graph.

              T : Output directed graphs in T-code. This is a simple ASCII output format. Every line

              contains  one  graph. First the number of vertices, then the number of directed edges and then the
              list of directed edges with the start first and the end then. E.g.: 3 2 0 1 2 1 means 3  vertices,
              2 directed edges: 0-->1 and 2-->1

              B : Output the directed graphs in a binary code. Every item of the code is an unsigned

              char.  The  first unsigned char is the number nv of vertices. The vertices are numbered 1..nv Then
              the list of vertices x for which there is a directed edge 1->x follow. This list is ended by a  0.
              Then  the  list  of  outgoing  neighbours  of 2 follows -- again ended with a 0, etc.  The code is
              complete with the 0 ending the list of outgoing neighbours of nv.

              C : Do really construct all the directed graphs in memory, but don't output them. This is not

              a big difference in case of restricted in- and outdegrees, because all that is done extra is  that
              edges  are  directed instead of just keeping track of in- and out-degrees. This option is intended
              only for testing purposes to test also routines that are normally not used when  counting.  Things
              that  would  speed  up  the  counting also in some cases of restricted in- and out-degrees -- like
              multiplying the possibilities of assigning directions to edges that  can  be  assigned  directions
              independent  of  each  other (depending on the degrees of the endvertices and overlaps) -- are not
              included.  In case of not restrictive bounds on the in- and out-degree it not really  constructing
              the  graphs  can  be  considerably  faster.  In  cases  of restricted in- and out-degrees the only
              difference is that the graph isn't modified...  The fact that in case of no output  the  graph  is
              not  modified  is  mainly to save time for the one case of waterclusters, where large numbers were
              determined. If large numbers (without output) for other cases  shall  be  determined,  one  should
              think about adding the multiplication routines.

              m : Read multicode instead of g6 code

       This program uses different labelling routines -- all based on the ideas of

       G.  Brinkmann, Generating water clusters and other directed graphs, Journal of Mathematical Chemistry 46,
       1112--1121 (2009)