v1.11.2

Graphs v1.11.2

Diff since v1.11.1

Merged pull requests:

• Fix bfs iterator for multiple source nodes (#382) (@Tortar)
• Bump version to 1.11.2 (#388) (@gdalle)

Closed issues:

• [OPTIM] perm_greedy_color (and thus all coloring algorithms) is running in O(n^2) instead of O(n) (#378)
• [FR] Construct a graph corresponding to a binary relation (#384)
• [FR] a function to efficiently check whether a graph is acyclic (#385)