Method value can be ''positive'' only if all edge weights are nonnegative. Graph edge weights contain NaN. No value given for Method. Shortest path distance undefined because the graph contains a negative cycle of length {0} (nodes {1}). Graph edge weights must be nonnegative. Source must specify one node. Target must specify one node. When Method value is ''acyclic'', directed graph must be acyclic. Parameter name must be ''Method''. Method value must be ''auto'', ''unweighted'', ''positive'', ''mixed'', or ''acyclic''. Method value must be ''auto'', ''unweighted'', or ''positive''.