METHOD AND APPARATUS FOR UPDATING A SHORTEST PATH GRAPH

A method and apparatus for updating a shortest path graph or a shortest path tree are disclosed. For example, an arc weight is changed for an arc in the network, where a plurality of affected nodes in the network is determined. The distance of each of the affected nodes is determined, where a subset of the plurality of affected nodes is then placed in a heap. One aspect of the present invention is that not all the affected nodes are placed in the heap. In one embodiment, the present reduced heap approach only applies the Dijkstra's algorithm to those affected nodes whose distances change in a smaller amount that the change in the arc weight. In turn, the shortest path graph or the shortest path tree is updated in accordance with the affected nodes placed in the heap.