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