1. CSC 110 – Fluency in Information Technology Chess
Dr. Curry Guinn

2. Today’s Class
A Look Ahead
Computer Chess
Lab

3. What’s Next? November 21 Fri Natural Language Processing
November 24 Mon Futuristic Stuff
November 26 Wed No Class
November 28 Fri No Class
December 1 Mon Review
December 3 Wed Exam #2
December 10 Wed Final Exam Due

4. Computer Chess
Chess playing machines have been around longer than computers
The Turk

5. The Turk 1769 Complicated gear works
Could beat very, very good players
It was a hoax.
The Turk: The Life and Times of the Famous Eighteenth-Century Chess-Playing Machine

6. Computer Chess Programs first developed in 1958
In 1997, Gary Kasparov lost a six game match to Deep Blue ( ).
The primary algorithm used is called MINIMAX.
How does it work?

7. Minimax relies on an Evaluation function
The Evaluation function rates how good a particular configuration is
In chess, the evaluation of a board position might include:
Number and type of pieces remaining on the board
How mobile are your pieces?
Do you control the center of the board?
Is the king in a safe position?

8. Minimax Algorithm See what moves are possible for you
Then for each of those moves, see what your opponent can do
Then for each of those moves, see what you can do …
Then see what your opponent can do …
And so on.
When you stop looking at possible moves, evaluate those final board positions.
Determine which sequence of moves will guarantee you the highest score.
You will always choose the move that results in a higher score;
Your opponent will always choose the move that results in a lower score

9. MAX A B C MIN D E F G MAX 1 1 -3 4 1 2 -3 4 -5 1 -7 2 -3 -8
= terminal position
= agent
= opponent

10. Problems with Minimax How far can you search in the tree?
In chess, between moves possible on average.
So at each level of the tree, you could have 25 branches.
After 1 move, 25 possible boards.
After 2 moves, 252 = 625
After 3 moves, 253 = 15, 625

11. Depth of Minimax After 4 moves, 254 = 390, 625…
After 10 moves, 2510 = 95, 367, 431, 640, 625
Searching to depth = 40, at one game per microsecond it would take 1090 years to make its first move
Age of universe = 1010

12. Depth of Minimax (Deep Blue)
480 specialty chess chips
Parallel computing: 30 workstations
Searches 12 plies (turns)
25^12 = 59 quadrillion
Extends promising lines as must as 40 plies
PLUS opening database
PLUS end-game algorithms

13. So Is It Intelligent?

14. Games where MiniMax doesn’t work too wellGo
Branching factor of 200
Games can go on for 250+ moves
Very difficult to evaluate board positions
This is the HOT game to study in AI
Card games
Too much variability due to chance

15. Lab: Part 1 Here’s another art program. It’s pretty good.

16. Lab: Play Chinook Chinook is the best checkers player in the world
Try it:

17. Some great AI demos and movies
A page with some of the best computer game players:

18. Wrap-up Why is Natural Language Processing so hard? Read this paper: