The final example in this chapter shows another way in which optimization can be used on problems that are completely unrelated to one another. In this case, the problem is the visualization of networks. A network in this case is any set of things that are connected together. A good example in online applications is a social network like MySpace, Facebook, or LinkedIn, where people are connected because they are friends or have a professional relationship. Each member of the site chooses to whom they are connected, and collectively this creates a network of people. It is interesting to visualize such networks to determine their structure, perhaps in order to find the people who are connectors (those who know a lot of people or who serve as a link between otherwise self-contained cliques).
When drawing a network to visualize a big group of people and the links between them, one problem is deciding where each name (or icon) should be placed in the picture. For example, consider the network in Figure 5-7.
Figure 5-7. A confusing network layout
In this figure, you can see that Augustus is friends with Willy, Violet, and Miranda. But the layout of the network is a bit messy, and adding more people would make it very confusing. A much cleaner layout is shown in Figure 5-8.
Figure 5-8. A clean network layout
This section will look at how optimization can ...