Warning

The documentation for retworkx has migrated to:

https://qiskit.org/documentation/retworkx

These docs will no longer be updated.

retworkx.digraph_union

digraph_union(first, second, merge_nodes, merge_edges, /)

Return a new PyDiGraph by forming a union from two input PyDiGraph objects

The algorithm in this function operates in three phases:

1. Add all the nodes from second into first. operates in O(n), with n being number of nodes in b.

2. Merge nodes from second over first given that:

   • The merge_nodes is True. operates in O(n^2), with n being the number of nodes in second.

   • The respective node in second and first share the same weight/data payload.

3. Adds all the edges from second to first. If the merge_edges parameter is True and the respective edge in second and first`` share the same weight/data payload they will be merged together.

param PyDiGraph first

The first directed graph object

param PyDiGraph second

The second directed graph object

param bool merge_nodes

If set to True nodes will be merged between second and first if the weights are equal.

param bool merge_edges

If set to True edges will be merged between second and first if the weights are equal.

returns

A new PyDiGraph object that is the union of second and first. It’s worth noting the weight/data payload objects are passed by reference from first and second to this new object.

rtype

PyDiGraph