seed = integer or none

Seed for the random number generator. When an integer is specified, this is equivalent to calling randomize(seed).

weights = range or function

If the option weights=m..n is specified, where $m\le n$ are integers, the graph returned is a weighted graph with edge weights chosen from [m,n] uniformly at random.  The weight matrix W in the graph has datatype=integer, and if the edge from vertex i to j is not in the graph then W[i,j] = 0.

If the option weights=x..y where $x\le y$ are floating-point numbers is specified, the graph returned is a weighted graph with numerical edge weights chosen from [x,y] uniformly at random.  The weight matrix W in the graph has datatype=float[8], that is, double precision floats (16 decimal digits), and if the edge from vertex i to j is not in the graph then W[i,j] = 0.0.

If the option weights=f where f is a function (a Maple procedure) that returns a number (integer, rational, or decimal number), then f is used to generate the edge weights.  The weight matrix W in the graph has datatype=anything, and if the edge from vertex i to j is not in the graph then W[i,j] = 0.

RandomDigraph(n,m) creates a directed unweighted graph on n vertices and m edges, where the m edges are chosen uniformly at random.

RandomDigraph(n,p) creates a directed unweighted graph on n vertices where each possible edge is present with probability p.

If the first input is a positive integer n, then the vertices are labeled 1,2,...,n.  Alternatively you may specify the vertex labels in a list.

The random number generator used can be seeded with the seed option or by using the randomize function.

$\mathrm{with}\left(\mathrm{GraphTheory}\right)\:$

$\mathrm{with}\left(\mathrm{RandomGraphs}\right)\:$

$G≔\mathrm{RandomDigraph}\left(10\,0.5\right)$

$G≔\mathrm{Graph\; 1:\; a\; directed\; graph\; with\; 10\; vertices\; and\; 39\; arc(s)}$

$\mathrm{IsDirected}\left(G\right)$

$\mathrm{true}$

$H≔\mathrm{RandomDigraph}\left(10\,20\right)$

$H≔\mathrm{Graph\; 2:\; a\; directed\; graph\; with\; 10\; vertices,\; 19\; arc(s),\; and\; 1\; self-loop(s)}$

$J≔\mathrm{RandomDigraph}\left(4\,6\,\mathrm{weights}=1..4\right)$

$J≔\mathrm{Graph\; 3:\; a\; directed\; weighted\; graph\; with\; 4\; vertices,\; 3\; arc(s),\; and\; 3\; self-loop(s)}$

$\mathrm{WeightMatrix}\left(J\right)$

$\left[\begin{array}{cccc}0& 4& 0& 0\\ 0& 2& 2& 0\\ 0& 0& 3& 3\\ 0& 0& 0& 2\end{array}\right]$