at this vertex.
</blockquote>

<h3>Named Parameters</h3>

IN: <tt>weight_map(WeightMap w_map)</tt>   
<blockquote>
  The weight or ``length'' of each edge in the graph.
  The type <tt>WeightMap</tt> must be a model of
  <a href="../../property_map/ReadablePropertyMap.html">Readable Property Map</a>. The edge descriptor type of
  the graph needs to be usable as the key type for the weight
  map. The value type for the map must be
  <i>Addable</i> with the value type of the distance map.<br>
  <b>Default:</b>