FALSE, a numeric value, or a symetric matrix of distances providing the desired lengths for all dyads.. If numeric, entries are written out for all possible dyads in the network, and the numeric value will be used to fill in the values for all the dyads in the matrix not linked by an edge (see default.dist param to layout.distance). This is necessary for some uses cases, but will generate dramatically larger files and slower performance. For the matrix and numeric cases, the values will be written as Graphviz 'len' edge attributes, and the values of edge.attrs will be ignored.
vert.attrs
optional character vector listing the names of any vertex attributes of the network that should be included as attributes of the nodes in the Graphviz dot file. (e.g. 'label', 'width')
edge.attrs
optional character vector listing the names of any edge attributes of the network that should be included as attributes of edges in the Graphviz dot file. (e.g. 'weight','penwidth')