Figure 4: Algorithm selection panel on the Sun platform
The first item in the selection list is Edit Graph, which can be used to return to the GraphControlPanel. Algorithms are selected by double clicking on the name of the algorithm. After selecting an algorithm, an algorithm control panel appears. Figure 5 shows the algorithm control panel, and Figure 7 shows the NetWorKs program with the algorithm control panel displayed.
Figure 5: Algorithm control panel on the Sun platform
The algorithm control panel has four buttons labeled restart, step, algorithms, and edit. The algorithms button will redisplay the selection panel, the restart button restarts the currently selected algorithm, and the step button executes one step of the algorithm. The edit button will redisplay the GraphControlPanel. Users may switch back and forth between the GraphControlPanel and the algorithm control panel as long as they only alter the appearance of the graph. If users add or delete edges or vertices, or if they edit the attributes--including color--of any edge or vertex, then they will have to reselect an algorithm.
Figure 6: NetWorKs GUI with the algorithm selection panel displayed
Figure 7: NetWorKs GUI with the algorithm control panel displayed
From a user's perspective, running an algorithm simply consists of selecting an algorithm from a list and then using the step button to step through the algorithm. The user may also decide to edit the graph or simply alter its appearance to better display the steps taken by the algorithm. Notice in Figure 8, that the Savannah vertex has been moved and the Dijkstra graph algorithm has found the shortest path tree from the vertex labeled Atlanta. The shortest path tree is indicated by the set of blue edges, which appear as the bold edges in Figure 8.
Figure 8: NetWorKs GUI with the algorithm completed