GOAL Guide

Main Features

GOAL is a Windows application, and the standard Windows methods for executing the application, opening documents an managing windows can be applied.

GOAL documents are divided into three sections, whose contents are:

	Definition of the parameters.
	Objective Function Code.
	Constraints Code.

Their sizes can be modified with the mouse.

Parameters Definition

Parameters are variables of the objective function that can be modified by the genetic algorithm during the optimization. To define a parameter, its name, type and bounds must be specified.

To define a new parameter, click on the button "Add" on the right of the parameters table. A dialog will show up in which these data can be introduced:

This data can be modified later by using the button "Modify", or deleted clicking on the button "Del". In both cases, the parameter that is to be deleted or modified must be selected clicking on a corresponding cell of the parameters table.

Objective Function

The objective function must be programmed using the Visual Basic Script programming language. Every instruction of this language can be used, including control sentences, loops and subs.

The code of the objective function must be written inside the VBScript function "ObjectiveFunction" .The final value of the objective function must be stored in a variable named "ObjectiveFunction". However, it is possible to invoke additional functions and procedures from the code written inside the "ObjectiveFunction".

Constraints

To define a new constraint, use the button "New" on the right of the constraints code editor. The following dialog will be opened, in which the user will be asked for a name for the new constraint. The function of this name is to make easy to remember the meaning of each constraint, so any descriptive name can be used.

If a new constraint is defined, a new tab will appear in the constraints code editor. Click on these tabs to get the code of respective constraints.

To delete a constraint, select the tab of the constraint that will be deleted, and click on the button "Del".

Constraints must be programmed using Visual Basic Script. In this program, objective function's parameters, as well as intermediate variables defined in the code of the objective function, can be used.

The code of a constraint must include a variable called "Constr_Number", which has a boolean value that indicates whether the constraint is fulfilled (Result = true) or not (Result = false).

Algorithm Parameters

Algorithm parameters can be modified with the following dialog, which shows up by selecting the "Options" command in the "Algorithm" menu:

In this dialog it can also be chosen if the optimum solutions found until that generation will appear during the optimization, and if the report generated by GOAL will be displayed at the end of the optimization.

Getting Results

To solve an optimization problem, click on the "Execute" button of the toolbar, or select this command in the "Algorithm" menu.

If the option "Show optimum solutions during optimization" has been selected in the "Genetic Algorithm Properties" dialog, the following dialog, which summarizes the best solutions found at the moment, will be displayed during the optimization. The first column shows the value of parameters, and the second one the value of the objective function:

When a solution has been obtained, GOAL shows this solution through the following dialog:

GOAL also generates automatically a report, named NameFile_Report.txt, which will be saved in the folder where the GOAL document is stored. The contents of the report are:

	Genetic Algorithm Parameters.
	Evolution of several parameters in each generation, including: mean and standard deviation of objective function values; number of reproductions and mutations; and the best solution found in that generation, including its parameters, genotype and objective function value.
	Best solution found at the end of the optimization.

This report will be displayed at the end of the optimization if the option "Show report" of the "Genetic Algorithm Properties" dialog has been selected.

Problem Codification

GOAL stores the document in a text file. Although it is easier to use the GOAL editor, you can use any text editor to write this file. Just like GOAL documents, that text file is divided into three sections:

	The first section stores the name, type and bounds of parameters.
	The second section contains the objective function code.
	The third section contains the name and code of constraints.

You can see several examples of these text files in the section "GOAL examples"

Help File

For more details, please refer to the help file provided with GOAL. This file can be opened by clicking in the "Help contents" command of the help menu.