This example shows to how visualize the maximum flow in a directed network, where edge strengths are interpreted as capacities.
Run KP, then load the file 'flow.kp' from the standard data directory.
Go to the menu item 'display!layout!anneal settings'. In the list of values, change 'weight on edges pointing downwards' to 100. Hit return, select the button 'Apply' from the bottom row. Close the 'Anneal settings' window.
Once a flow is initialized, it is computed as soon as a source and sink are given, and recomputed whenever the graph is changed. Some of the links should now be partially red. The amount of red shows the amount of capacity on the link that is used in the flow. If you right-click on the link, you will see both the flow and the capacity in the menu. For example, the link E->F has strength = 9 and flow = 5. This version of the algorithm accepts multiple sources and sinks. Because the Ford-Fulkerson algorithm searches for arbitrary paths from a source to a sink, the order in which you select objects will determine the flow found, but not the max flow value.
You can alter the capacity of a link through a spinner by right-clicking on the link and selecting the 'strength=..' entry. As the capacity is changed, the flow is recomputed. You can also block and unblock nodes and links by right-clicking over them, and the flow is again recomputed automatically.
To see a larger graph with flow, load 'pipeline1.mif' from the standard directory. After selecting 'initialize flow', also select 'ignore link direction' also from the simulation menu. In this graph, nodes are colored red or orange when there is flow through the node. You can drag any node on the flow, and all the nodes with flow will move together, making it easier to see the path of the flow.