Fitness Function Cell
Select a Fitness Function Cell by either highlighting it in your spreadsheet prior to starting GeneHunter, typing in the cell reference in the edit box, or using your mouse to select the desired cell directly on the spreadsheet when the GeneHunter dialog box is on the screen. (You may have multiple Fitness Functions. Refer to Multiple Fitness Functions for Details.) You must specify whether you want this fitness function cell to reach a maximum, minimum, or specific value by clicking on either the Min or Max button or typing a value in the edit box.
The Fitness Function tells GeneHunter the location of the cell that contains the formula that measures GeneHunter’s success in finding a solution to your problem. The formula may be created using any of the Excel functions that are available from the Insert Menu, such as average. You may also use Excel Visual Basic for Applications (VBA) functions to create fitness functions that allow you to solve very complex problems.
GeneHunter measures success by searching for three different types of values:
Maximum If “Maximum” is selected, GeneHunter will search for variable values in the adjustable chromosomes that produce the largest possible number in the Fitness Function Cell.
Minimum If “Minimum” is selected, GeneHunter will search for variable values in the adjustable chromosomes that produce the smallest possible number in the Fitness Function Cell.
Value of If “Value of” is selected, GeneHunter will search for variable values in the adjustable chromosomes that produce the number in the Fitness Function Cell which is closest to the value entered in the Edit Box. For example, if the number in the Edit Box is 200, GeneHunter will examine solutions that produce values such as 197 and 205. It does not matter to GeneHunter whether the value is greater than or less than the specified value. It will optimize on the value closest to the value entered in the Edit Box. In the above example, GeneHunter would consider 197 to be closer to 200 than 205.
In the Camping Trip example (described in Chapter 4 and included in the GHSAMPLE.XLS spreadsheet that was installed in your \GENEHUNTER\EXAMPLES\EXCEL directory during Setup), the goal is to minimize the food budget. If you were creating a sales application that considered variables such as the advertising, distributing, and research and development budgets, the goal might be to maximize revenue and you would want to maximize the fitness function. In another application, the goal might be to raise a certain number of dollars while varying the number of hours worked by volunteers and the amount spent on advertising. In this case, you would enter the dollar value in the Value edit box.