CAGE User's Guide

User-Defined Optimization

User-defined optimizations are described in the following sections:

• Implementing Your Optimization Algorithm in CAGE is an overview of how to customize the optimization template to use your optimization routines in CAGE.

• There is a step-by-step guide to using the worked example provided to help you understand how to modify the template file to use your own optimization functions. See Worked Example Optimization in the optimization tutorial.

• Optimization Template describes the details of the available subroutines for customizing each section of the template file.

Introduction to Writing User-Defined Optimizations

In many cases the standard routines supplied for constrained single and multiobjective optimization (foptcon and NBI) are sufficient to allow you to solve your optimization problem. Sometimes, however, you need to write a customized optimization algorithm. This can be useful in many situations, for example,

• For an expert to capture an optimization process to solve a particular problem, for example, determination of optimal spark angle and exhaust gas recirculation rate on a port-fuel injection engine
• To implement an alternative optimization algorithm to those supplied
• To implement a complex constraint or objective that is only possible through writing M-code
• To produce custom output graphics

User-defined optimization functions in CAGE allow advanced users to write their own optimization routines that can access current CAGE data. In order to access the user function from CAGE, you must register the M-file with CAGE and place it on the MATLAB path. It is crucial that this function conform to the template specified. The following sections describe this process.

Implementing Your Optimization Algorithm in CAGE

At some point a CAGE optimization function calls on an algorithm to optimize the objective functions over the free variables. You can implement the algorithm in the CAGE optimization function as an external M-file. You use the template file as a basis for your optimization function. The best way to understand how to alter the template file to implement your own optimization algorithms is to compare it with the worked example, as described in the optimization tutorial.

• Worked Example Optimization describes the process of using the worked example.
• About the Worked Example Optimization Algorithm examines the coding involved in implementing an external optimizer in a CAGE optimization M-file.
• The optimization tutorial section Creating an Optimization from Your Own Algorithm describes in detail the steps necessary to use an example optimization algorithm in CAGE.

What Are Appropriate Optimizations?

Overview of Optimization Function Structure