# Module Imperative.Matrix.Digraph

    module Digraph: S

Imperative Directed Graphs implemented with adjacency matrices.

Vertices are integers in `0..n-1`. A vertex label is the vertex itself. Edges are unlabeled.

    include Sig.I

    val make : int -> t

Creation. graphs are not resizeable: size is given at creation time. Thus `make` must be used instead of `create`.
Note: `add_vertex` and `remove_vertex` have no effect. `clear` only removes edges, not vertices.