For the circuit simulator I need a way to find parallel paths in a graph. To prepare the actual parallel path detection I first need to split a given path into a set of subpaths wich start and end at nodes spawning multiple branches. After some thinking I found out following algorithm:

public Set<Path<V>> apply(Graph<V> graph, PathStar.Parameters<V>... parameters) { assert graph != null; assert parameters != null; assert parameters.length > 0; PathStar.Parameters<V> params = parameters[0]; Set<Path<V>> paths = new HashSet<>(); List<Node<V>> subPath = new LinkedList<>(); Iterator<Node<V>> pathIterator = params.getPathToSplit().iterator(); while (pathIterator.hasNext()){ Node<V> node = pathIterator.next(); subPath.add(node); Set<Edge<V>> edges = new HashSet<>(graph.getEdges(node)); if (pathIterator.hasNext()){ Iterator<Edge<V>> iterator = edges.iterator(); while (iterator.hasNext()){ Edge<V> edge = iterator.next(); Node<V> previousNode = params.getPathToSplit().getPredecessor(node); try { if (previousNode != null && edge.getTarget(node).equals(previousNode)){ iterator.remove(); } } catch (DestinationNotExistsException ignored){ } catch (EdgeException e) { throw new RuntimeException(e); } } } if (edges.size() > 1){ if (subPath.size() > 1){ paths.add(new Path<>(subPath)); } if (!pathIterator.hasNext()){ subPath = new LinkedList<>(); break; } subPath = new LinkedList<>(Collections.singleton(node)); } } if (subPath.size() > 0){ subPath.add(params.getPathToSplit().iterator().next()); paths.add(new Path<>(subPath)); } return paths; }

## How it works

- Init new list of nodes representing the current subpath
- For every node of the given path do following steps:
- Add the node to the subpath
- If the currrent node is not the end node to the following steps:
- If the current node has multiple successors:
- Add current subpath to the list of found subpaths
- If the current node is the end node do the following steps:
- Create new empty subpath
- If the current subpaths has more than 1 node, add it to the list of found subpaths
- Return the list of found subpaths

- Create new subpath containing current node as its starting node

- If the current node has multiple successors:

- If the current subpaths has more than 1 node, add it to the list of found subpaths
- Return the list of found subpaths