NAUTY-WATERCLUSTER2(1)           Nauty Manual           NAUTY-WATERCLUSTER2(1)

       nauty-watercluster2 - generate small digraphs with given underlying
       graph (faster alternative to directg)

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

              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)

nauty 2.6.12                     October 2019           NAUTY-WATERCLUSTER2(1)