The links are then sorted accordingly, and each estimate is multiplied by a weight. The weighted estimates are normalized and used as probabilities by a stochastic selector. The weights represent the adaptive part of the agent's search strategy. They evolve by selection, reproduction, and mutation. When a link is selected, the agent traverses it and finds itself in a new document.
Any traversal incurs an energy cost.
The amount of energy an agent receives by finding a document is determined by its relevance, which in turn is estimated by a precision measure from standard IR theory. Each agent can also decide to present any document to the user hoping to get bonus energy. The user optionally provides feedback by increasing or decreasing the agent's energy. The search ends when the population gets extinct, converges according to some measure, or is terminated by the user. The total number of links is 178, while 26 of the documents contain a total of 149 query words occurrences.