Finding cycle of 3 nodes ( or triangles) in a graph

Question

I am working with complex networks. I want to find group of nodes which forms a cycle of 3 nodes (or triangles) in a given graph. As my graph contains about million edges, u

Answer 1

Surprised to see no mention of the Networkx triangles function. I know it doesn't necessarily return the groups of nodes that form a triangle, but should be pretty relevant to many who find themselves on this page.

nx.triangles(G) # list of how many triangles each node is part of
sum(nx.triangles(G).values())/3 # total number of triangles

An alternative way to return clumps of nodes would be something like...

for u,v,d in G.edges(data=True):
    u_array = adj_m.getrow(u).nonzero()[1] # get lists of all adjacent nodes
    v_array = adj_m.getrow(v).nonzero()[1]
    # find the intersection of the two sets - these are the third node of the triangle
    np.intersect1d(v_array,u_array)