4.1 Depth-First Single Step

• This exercise is aimed at (i) helping you to refine your own understanding of the operation of the Depth-First search method; and (ii) acquainting you with the operation of the AI-Search software for subsequent activities.

• Click on this button to start the AI-Search software.

• Now the animation software is running, and you have resized the application window to suit, select the Depth-First Search algorithm from the Algorithm menu.

• Select the Single Step with/without Algorithm from the Mode menu.

• Select Display Algorithm (yes) from the Settings menu.

• Set the following 8-Puzzle problem using the options from the Problem menu.

  Start Board 0 2 3 1 4 5 8 7 6

  Goal Board 1 2 3 8 4 5 0 7 6

• Begin single-stepping through this problem, watching and verifying the algorithm text coincides with the algorithm animation. Use the buttons labelled Start, Next, Back, Reset.

• When the goal is reached, the solution path will be highlighted and a small dialog box will appear. Take note of the length of the solution path, and the number of nodes in the open and closed sets. Then to continue click the Ok button in the small "Goal Found!" dialog box.

• Now click the mouse pointer on the Reset button; set the following problem; and single-step through it until the goal is reached.

  Start Board 0 2 3 1 4 5 8 7 6

  Goal Board 1 0 3 8 2 5 7 4 6

• Click on the Reset button so that new animation options can be selected when you advance to the next exercise.