Add set_branch_orientations utility function

[Thijss]

Adds two new Grid functions:

    def get_reversed_branches(self) -> BranchArray:
        """Get the branch array of branches that are oriented towards the source(s).

        Orientation is determined by the distance of the branch's from_node and to_node to the source node.
        The node that is closer to the source is considered the "from_node".
        Note that this might not reflect the actual power flow direction in the grid.

        - If a source is connected to another source. The orientation will be set from the perspective of
          the source with the lowest node id.
        - Parallel edges (multiple edges between the same two nodes) and cycles are supported.
        - Open branches will be corrected so that the from_status is 1 and the to_status is 0.

        Returns:
            BranchArray: All branches that are oriented towards the source(s)
        """
        return get_reversed_branches(self)

    def set_branch_orientations(self) -> BranchArray:
        """Set branch orientations in the grid so that all branches are oriented away from the sources.
        See also get_reversed_branches() for how the branches to reverse are determined.

        Returns:
            BranchArray: All branches that were reversed.
        """
        return set_branch_orientations(self)

Todo

• On second thought, I think we can allow fixing branches on cycles after all.

Piggyback

• Add BaseGraph.has_parallel_edges()

Performance

I did some testing on our production data

93790 branches to consider
fix_branch_orientations took 8.61 seconds
1226 branches are reversed

[Copilot]

Pull request overview

This PR adds a new utility function fix_branch_orientations() to automatically orient all branches in a grid away from source nodes. The function ensures that in a radial network topology, all branches flow outward from the sources, which is important for power flow calculations and network analysis.

Changes:

• Added fix_branch_orientations() utility function that reorients branches to flow away from sources
• Added has_parallel_edges() method to the graph model interface to detect parallel edges
• Added comprehensive test coverage for both new features

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
src/power_grid_model_ds/utils.py	New file containing the fix_branch_orientations() function and helper functions for branch orientation fixing
src/power_grid_model_ds/_core/model/graphs/models/base.py	Added abstract method has_parallel_edges() to the base graph model interface
src/power_grid_model_ds/_core/model/graphs/models/rustworkx.py	Implemented has_parallel_edges() by delegating to rustworkx's built-in method
tests/unit/test_utils.py	New test file with comprehensive tests for fix_branch_orientations() covering basic functionality, dry-run mode, cycle detection, connected sources, and parallel edges
tests/unit/model/graphs/test_graph_model.py	Added tests for has_parallel_edges() method, including both same-direction and reversed parallel edges

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[jaapschoutenalliander]

I have some input on the setup but overall it looks good and I think it is a useful util function

[vincentkoppen]

Looks good!
Some remarks, but nice functionality to add :)

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

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