# digraph.diameter() returning +Infinity for some cases

I'm running Sage 6.4.1 on OS X (Yosemite). Creating a directed graph with `n`

vertices (for any n that I tried) returned `+Infinity`

. EG:

```
sage: digraphs.Path(10).diameter()
+Infinity
```

or even

```
sage: digraphs.ButterflyGraph(5).diameter()
+Infinity
```

However, both of these Path and Butterfly graphs are finite, connected, directed acyclic graphs so their diameter should always be finite.

The

underlyinggraph is connected. But if you type: digraphs.Path(10).show() you'll see a path from 1 to 2 to 3 and so on. So there is no directed path, for example, from 2 to 1. The distance from 2 to 1 is infinite but the distance from 1 to 2 is one. The diameter is just the maximum of the distances so it has to be infinite.