| standard library package TradeStudies { | |
| doc | |
| /* | |
| * This package provides a simple framework for defining trade-off study analysis cases. | |
| */ | |
| private import Base::Anything; | |
| private import ScalarValues::*; | |
| private import ScalarFunctions::*; | |
| private import ControlFunctions::*; | |
| abstract calc def EvaluationFunction { | |
| doc | |
| /* | |
| * An EvaluationFunction is a calculation that evaluates a TradeStudy alternative, | |
| * producing a ScalarValue that can be comparted with the evaluation of other | |
| * alternatives. | |
| */ | |
| in ref alternative : Anything { | |
| doc | |
| /* | |
| * The alternative to be evaluated. | |
| */ | |
| } | |
| return attribute result : ScalarValue[1] { | |
| doc | |
| /* | |
| * A ScalarValue representing the evaluation of the given alternative. | |
| */ | |
| } | |
| } | |
| abstract requirement def TradeStudyObjective { | |
| doc | |
| /* | |
| * A TradeStudyObjective is the base definition for the objective of a TradeStudy. | |
| * The requirement is to choose from a given set of alternatives the selectedAlternative | |
| * for that has the best evaluation according to a given EvaluationFunction. What | |
| * value is considered "best" is not defined in the abstract base definition but must be | |
| * computed in any concrete specialization. | |
| */ | |
| subject selectedAlternative : Anything { | |
| doc | |
| /* | |
| * The alternative that should be selected, as evaluated using the given | |
| * ObjectiveFunction. | |
| */ | |
| } | |
| in ref alternatives : Anything[1..*] { | |
| doc | |
| /* | |
| * The alternatives being considered in the TradeStudy for which this TradeStudyObjective | |
| * is the objective. | |
| */ | |
| } | |
| in calc fn : EvaluationFunction { | |
| doc | |
| /* | |
| * The EvaluationFunction to be used in evaluating the given alternatives. | |
| */ | |
| } | |
| out attribute best : ScalarValue { | |
| doc | |
| /* | |
| * Out of the evaluation results of all the given alternatives, the one that is considered | |
| * "best", in the sense that it is the value the selectedAlternative should have. This | |
| * value must be computed in any concrete specialization of TradeStudyObjective. | |
| */ | |
| } | |
| require constraint { fn(selectedAlternative) == best } | |
| } | |
| requirement def MinimizeObjective :> TradeStudyObjective { | |
| doc | |
| /* | |
| * A MinimizeObjective is a TradeStudyObjective that requires that the | |
| * selectedAlternative have the minimum ObjectiveFunction value of all the | |
| * given alternatives. | |
| */ | |
| subject :>> selectedAlternative; | |
| in ref :>> alternatives; | |
| in calc :>>fn; | |
| out attribute :>> best = alternatives->minimize { | |
| doc | |
| /* | |
| * For a MinimizeObjective, the best value is the minimum one. | |
| */ | |
| in x; fn(x) | |
| }; | |
| } | |
| requirement def MaximizeObjective :> TradeStudyObjective { | |
| doc | |
| /* | |
| * A MaximizeObjective is a TradeStudyObjective that requires that the | |
| * selectedAlternative have the maximum ObjectiveFunction value of all the | |
| * given alternatives. | |
| */ | |
| subject :>> selectedAlternative; | |
| in ref :>> alternatives; | |
| in calc :>>fn; | |
| out attribute :>> best = alternatives->maximize { | |
| doc | |
| /* | |
| * For a MinimizeObjective, the best value is the maximum one. | |
| */ | |
| in x; fn(x) | |
| }; | |
| } | |
| abstract analysis def TradeStudy { | |
| doc | |
| /* | |
| * A TradeStudy is an analysis case whose subject is a set of alternatives | |
| * (at least one) and whose result is a selection of one of those alternatives. | |
| * The alternatives are evaluated based on a given ObjectiveFunction and the | |
| * selection is made such that it satisfies the objective of the TradeStudy | |
| * (which must be a TradeStudyObjective). | |
| */ | |
| subject studyAlternatives : Anything[1..*] { | |
| doc | |
| /* | |
| * The set of alternatives being considered in this TradeStudy. | |
| * | |
| * In a TradeStudy usage, bind this feature to the actual collection of | |
| * alternatives to be considered. | |
| */ | |
| } | |
| abstract calc evaluationFunction : EvaluationFunction { | |
| doc | |
| /* | |
| * The EvaluationFunction to be used to evaluate the alternatives. | |
| * | |
| * In a TradeStudy usage, redefine this feature to provide the desired | |
| * calculation (or bind it to a calculation usage that does so). | |
| */ | |
| } | |
| objective tradeStudyObjective : TradeStudyObjective { | |
| doc | |
| /* | |
| * The objective of this TradeStudy. | |
| * | |
| * Redefine this feature to give it a definition that is a concrete | |
| * specialization of TradeStudyObjective. That can either be one of the | |
| * specializations provided in this package, or a more specific user- | |
| * defined one. | |
| */ | |
| subject :>> selectedAlternative; | |
| in ref :>> alternatives = studyAlternatives; | |
| in calc :>> fn = evaluationFunction; | |
| } | |
| return selectedAlternative : Anything = studyAlternatives->selectOne {in ref a { | |
| doc | |
| /* | |
| * The alternative selected by this TradeStudy, which is the one that meets the | |
| * requirement of the tradeStudyObjective. | |
| */ | |
| } tradeStudyObjective(selectedAlternative = a)}; | |
| } | |
| } |