View source for Identifying the Source of an Extrinsic Index

[[Category: Analytica Optimizer Guide]]
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Due to Analytica’s efficiency in array abstraction, you may occasionally find that you have inadvertently propagated an extrinsic index through your optimization model. If it is a very complex model, this can have an unpleasant effect on memory loads and computation times. It can also be difficult to trace the source of the error. 

The [[OptInfo]]() function in Analytica Optimizer 4.3 includes “Extrinsic Indexes” as a convenient new item designed for this purpose. Even more conveniently, you don’t even have to use the [[OptInfo]]() function to see this result. All OptInfo items are accessible by double-clicking the encoding object displayed when you evaluate [[DefineOptimization]]().

Evaluate the Optimization node and set the view to Sample mode.

Double-click on the optimization encoding object: «NLP»

In the next view, double click the reference object next to '''Extrinsic Indexes'''.

[[File:nlp_mod5_2.png|500px]]

In a complex model, you may have many Decisions and Constraints. The [[OptInfo]]() view would identify the specific arrays that contain various extrinsic indexes. In this example the '''Time''' index is traced to the Objective. 

The final window here would also displayed by OptInfo(Opt, "Extrinsic Indexes"). See the [[Optimizer_Function_Reference|Optimizer Function Reference]] chapter in this guide for a list of all [[OptInfo]]() items.

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