======================= Knowledge and Reasoning ======================= The knowledge engine is able to infer parameters of a designator description from the context given by the properties attached to its parameters. Since the properties are defined for the parameters of a designator description they add semantic information to the designator description parameters. The knowledge engine is able to utilize this information to infer the value of a parameter from the context. Inference is done very similar to the normal reasoning process where the property function of the designator description is first resolved and then evaluated. The difference is that we now not only look at the result (if the properties are satisfied or not) but also a the possible parameter solutions that are generated while reasoning. We start again by taking the properties of of the designator description and resolve them. This was already explained in the :ref:`Knowledge ` documentation. .. image:: ../images/knowledge/property_resolution.png :alt: Source Resolve :align: center We then evaluate the properties and generate the possible parameter solutions. .. image:: ../images/knowledge/property_evaluation.png :alt: Source Evaluate :align: center As can be seen in the picture above the major part of inferring missing parameter is done by the Knowledge Source with the semantic context provided by the properties. The magics consists now of matching the inferred parameter from the Knowledge Sources with the parameter of the designator description. ------------------------------- Matching of inferred parameters ------------------------------- The parameter that are inferred by the Knowledge Source during reasoning need to be matched to the designator to be usable in the execution of a designator. Matching of the inferred parameters is kinda ambiguous since the parameter are provided by the Knowledge Source as a dictionary with a name and the value. Therefore the name given in the dictionary might not match the designator. To solve the issue of aligning the inferred parameters from the Knowledge Source with the parameters of the designator we employ two methods. The first is to match the names in the dictionary with the names of the parameters of the designator. This is most reliable when the return from the Knowledge Source tries to adhere to the conventions of the designator description. The second method is to match the type of the inferred parameter with the type annotations in the designator. While this seems like the more reliable method, it cloud happen that a designator has multiple parameters of the same type. In this case the matching might not yield the correct result, since the first found parameter of the designator is matched with the parameter of the Knowledge Source.