├── README.md
└── k_shortest_paths.py


/README.md:
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1 | k_shortest_paths contains a function with the same name. This function uses Networkx (version 2.2.0).
2 | Said function computes the k shortest paths using Yen's algorithm (https://en.m.wikipedia.org/wiki/Yen%27s_algorithm)
3 | 


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/k_shortest_paths.py:
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 1 | import networkx as nx
 2 | import copy as cp
 3 | 
 4 | def k_shortest_paths(G, source, target, k = 1, weight = 'weight'):
 5 |     # G is a networkx graph.
 6 |     # source and target are the labels for the source and target of the path.
 7 |     # k is the amount of desired paths.
 8 |     # weight = 'weight' assumes a weighed graph. If this is undesired, use weight = None.
 9 |     
10 |     A = [nx.dijkstra_path(G, source, target, weight = 'weight')]
11 |     A_len = [sum([G[A[0][l]][A[0][l + 1]]['weight'] for l in range(len(A[0]) - 1)])]
12 |     B = []
13 | 
14 |     for i in range(1, k):
15 |         for j in range(0, len(A[-1]) - 1):
16 |             Gcopy = cp.deepcopy(G)
17 |             spurnode = A[-1][j]
18 |             rootpath = A[-1][:j + 1]
19 |             for path in A:
20 |                 if rootpath == path[0:j + 1]: #and len(path) > j?
21 |                     if Gcopy.has_edge(path[j], path[j + 1]):
22 |                         Gcopy.remove_edge(path[j], path[j + 1])
23 |                     if Gcopy.has_edge(path[j + 1], path[j]):
24 |                         Gcopy.remove_edge(path[j + 1], path[j])
25 |             for n in rootpath:
26 |                 if n != spurnode:
27 |                     Gcopy.remove_node(n)
28 |             try:
29 |                 spurpath = nx.dijkstra_path(Gcopy, spurnode, target, weight = 'weight')
30 |                 totalpath = rootpath + spurpath[1:]
31 |                 if totalpath not in B:
32 |                     B += [totalpath]
33 |             except nx.NetworkXNoPath:
34 |                 continue
35 |         if len(B) == 0:
36 |             break
37 |         lenB = [sum([G[path[l]][path[l + 1]]['weight'] for l in range(len(path) - 1)]) for path in B]
38 |         B = [p for _,p in sorted(zip(lenB, B))]
39 |         A.append(B[0])
40 |         A_len.append(sorted(lenB)[0])
41 |         B.remove(B[0])
42 |         
43 |     return A, A_len
44 | 


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