Light-Bot Interactive Applet

You can click the Start button to begin immediately, or adjust the parameters first. The "Pop Size" parameter sets the constant size of the population. The "Allow Duplicates" checkbox indicates whether or not the population is allowed to contain several identical members. If this box is unchecked, then any time a mutation/recombination results in a program that already exists in the population, it will be discarded, and a new random program will be added instead.

The "Recombine Sections" parameter sets the number of sections that each parent is divided into during a recombination. For example if this is set to 3, then each parent will be divided into 3 pieces of random length in the same way, and the child will be formed by taking the first and last piece from one parent and the middle piece from the other parent.

The "Mutation Width" parameter sets the number of commands affected by a mutation. The "Protect Leader" parameter specifies whether or not the highest ranked program can be changed by a mutation. This may be desirable to prevent bad mutations from reverting progress.

Parameters

Generation

Start over

Don't stop
Stop on improvements
Stop on first solution

The population of organisms/programs is in the box below. The twenty-eight commands are laid out horizontally, but they are still implicitely divided into the main, f1, and f2 sections. The numbers on the right of each program represent the number of targets lit by that program, and its length, respectively. Length is computed as the total number of active commands (by which I mean five commands that move the robot and light targets) executed, counting the commands in the functions once for each time they are executed. The programs are ranked according to the number of targets lit, and correct solutions are ranked further by their length (shorter programs are better). This is so that after the algorithm finds a solution, it will continue searching for shorter solutions.

You can run the algorithm in two modes, using the two blue buttons on the left. The first button runs the algorithm continuously, and you can watch as the population is updated. The second button lets you step through the algorithm and see exactly what is happening at each step. When running the algorithm continuosly, you can use the radio buttons to cause it to stop at certain interesting moments, such as an improvement (when a new program is generated that is better than all currently existing programs) or a first solution (when a new program is generated that correctly solves the board for the first time).

At any time you can click on any of the programs to load them into the viewer above, in order to watch them executed on the board.