advanced patterns in Dijkstra's Algorithm Implementation - Returning Negative Weights in Results
I'm converting an old project and I keep running into Could someone explain I'm working on a project and hit a roadblock..... I'm currently working on implementing Dijkstra's algorithm in Python for a simple graph application using the `networkx` library (version 2.5). I’ve constructed a graph with both positive and negative weights, and I'm running into an unexpected behavior where the shortest paths returned occasionally include negative weights, which shouldn't be possible according to the algorithm's principles. Here’s a snippet of my code where I create the graph and use Dijkstra's algorithm: ```python import networkx as nx # Create a directed graph G = nx.DiGraph() # Add edges with weights (including negative weights) G.add_edge(1, 2, weight=4) G.add_edge(2, 3, weight=-5) G.add_edge(1, 3, weight=10) # Attempt to find the shortest path from node 1 to node 3 shortest_path = nx.dijkstra_path(G, source=1, target=3) path_length = nx.dijkstra_path_length(G, source=1, target=3) print('Shortest path:', shortest_path) print('Path length:', path_length) ``` When I run this, the output I receive is: ``` Shortest path: [1, 2, 3] Path length: -1 ``` This result is confusing because Dijkstra's algorithm should only work with non-negative weights, and I expected it to raise an behavior or provide an incorrect path instead of resolving to a negative path length. I’ve double-checked my understanding and implementation and ensured that I'm passing in the correct parameters. Has anyone else faced this scenario when dealing with graphs with negative weights in `networkx`? I would appreciate any insights on how to handle this situation or if there's a particular reason this behavior is occurring. For context: I'm using Python on Linux. I'm coming from a different tech stack and learning Python. Thanks, I really appreciate it! This is my first time working with Python stable. Any pointers in the right direction? The project is a mobile app built with Python. Has anyone dealt with something similar?