Optimization of interactively defined functions - Instructions

Note: This option is not supported in applet mode (when run in a browser).


General

- The GA Playground supports interactive definition of functions for optimization.
- The expression can be arbitrarily long or complex
- The function should be defined as a single expression (single logical line).


Limitations

- Available only when GA Playground is run as an application
- Constraints as expressions are not supported (only as numerical ranges)


Expression to optimize

- Enter or modify a mathematical expression you wish to optimize.
- The variables names should be x1,x2,x3..x20
- Up to 20 variables are currently supported.
- All arithmetical operators are supported (+,-,*,/ etc.)
- Mathematical Java functions are supported (sin(x1),pow(x1,x2) etc.).
- Note: Power expressions should have the form pow(x1,x2) and not x1^x2.
- The expression string can be cut into different lines for convenience.


Common minimum/maximum values

- These are range constraints common to all parameters/arguments.
- To assign different ranges to different parameters use the Alleles Definition Table.


Number of Genes

- This setting defines the chromosome length, or total number of genes
- This setting is not necessarily identical to the number of variables
- With low number of variables it is recommended to increase genes number
- Number of genes must be a whole number multiplication of number of variables


Number of variables
- The number of distinct parameters or arguments to the function
- See above for relation between variables number and genes number


Exit Value

- This setting defines when the optimization process should stop
- Enter the desired function value with an adequate tolerance
- If the Exit Value is not reached, the process can always be stopped manually


Optimization mode

- Select either minimzation or maximization.


Credit

The interactive function optimization code is based on the Java Expressions Library (JEL), 
an amazing library that enables fast evaluation of dynamic string expressions.
The library was written by Konstantin Metlov (metlov@fzu.cz), 
whose site is at http://galaxy.fzu.cz/JEL/.