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Value/Estimate Incompatibility

  Incompatible suggestions for values and estimates can occur in two ways.

The first is when there are two agents with the same target and the suggested values or estimates are incompatible. This will cause a conflict because only one value or estimate may be stored in the target entity. This situation is shown in figure 5.6. Both agents have to have the same type, selector or estimator. So the conflict is between two selectors or two evaluators. The points of view of the conflicting agents have to be different else the agents would be identical.

  
Figure 5.6: Incompatible suggestions for the same value/estimate entity

The second kind of conflict can occur between two entities across parameters. This happens when the value of one parameter is not compatible with the value of the other parameter as shown in figure 5.7. The two value entities have to be in different parameter blocks since each parameter can have only one value entity. This type of conflict is possible only between two selectors. As a simple example, consider the case in the wine glass design where the a base radius selector generates a value for the base radius and then checks the internal constraint that the base radius has to be greater than the stem radius. If this constraint is violated, then the base radius selector will be in conflict with the stem radius selector.

  
Figure 5.7: Incompatible suggestions for different value entities



Ilan Berker
Thu Apr 27 16:25:38 EDT 1995