# Random Graphs¶

erdrey

An adjacency matrix of an Erdős–Rényi random graph: an undirected graph is chosen uniformly at random from the set of all symmetric graphs with a fixed number of nodes and edges. For example:

julia> matrixdepot("erdrey", 5, 3) # an undirected graph with 5 nodes and 3 edges.
5x5 sparse matrix with 6 Float64 entries:
[3, 1]  =  1.0
[3, 2]  =  1.0
[1, 3]  =  1.0
[2, 3]  =  1.0
[5, 4]  =  1.0
[4, 5]  =  1.0

gilbert
An adjacency matrix of a Gilbert random graph: each possible edge occurs independently with a given probability.
smallworld

Motivated by the small world model proposed by Watts and Strogatz [wast98], we proposed a random graph model by adding shortcuts to a kth nearest neighbor ring (node $$i$$ and $$j$$ are connected iff $$|i-j| \leq k$$ or $$|n - |i-j|| \leq k$$).

 [wast98] D.J. Watts and S. H. Strogatz. Collective Dynamics of Small World Networks, Nature 393 (1998), pp. 440-442.