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"Intelligent" CS 5

"Intelligent" CS 5. EXAM 2. Hw 10 due 11/15. Mon/Tue. An object is structured data that is alive, responsible, and intelligent. Sound too friendly?. This week’s objects and classes will be just the opposite. | | | | | | | | | | | | | | | | | | | | | | | | | | | |X| | | |

oliver-torres
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"Intelligent" CS 5

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  1. "Intelligent" CS 5 EXAM 2 Hw 10 due 11/15 Mon/Tue An object is structured data that is alive, responsible, and intelligent. Sound too friendly? This week’s objects and classes will be just the opposite ... | | | | | | | | | | | | | | | | | | | | | | | | | | | |X| | | | | |X| |X|O| | | |X|O|O|O|X|O| | --------------- 0 1 2 3 4 5 6 X to move. Is there a way to win?

  2. Coding Style deftomorrow(self): """Changes the calling object so that it represents one calendar day after the date it originally represented. """ if self.month in [1,3,5,7,8,10] and self.day == 31: self.day = 0 self.month += 1 elif self.month in [4,6,9,11] and self.day == 30: self.day = 0 self.month += 1 elif self.month == 2: if self.isLeapYear() and self.day == 29: self.day = 0 self.month += 1 elif (self.isLeapYear() == False) and self.day == 28: self.day = 0 self.month += 1 elif self.month == 12 and self.day == 31: self.day = 0 self.month = 1 self.year += 1 self.day += 1

  3. Better Style, But... deftomorrow(self): """Changes the calling object so that it represents one calendar day after the date it originally represented. """ DIM = [0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31] if self.isLeapYear() == True: DIM = [0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31] self.day += 1 if self.day > DIM[self.month]: self.day = 1 self.month += 1 if self.month > 12: self.month = 1 self.year += 1 else: self.day += 1 if self.day > DIM[self.month]: self.day = 1 self.month += 1 if self.month > 12: self.month = 1 self.year += 1

  4. An Elegant Solution def tomorrow(self): """Changes the calling object so that it represents one calendar day after the date it originally represented. """ DIM = [0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31] if self.isLeapYear(): DIM[2] = 29 self.day += 1 if self.day > DIM[self.month]: self.day = 1 self.month += 1 if self.month > 12: self.month = 1 self.year += 1

  5. isBefore/isAfter defisBefore(self, d2): """ Returns true if self is before d2 """ if self.year < d2.year: returnTrue if self.month < d2.month and self.year == d2.year: returnTrue if self.day < d2.day and d2.month == self.month and \ self.year == d2.year: returnTrue returnFalse defisAfter(self, d2): """ Returns true if self is after d2 """ if self.year > d2.year: returnTrue if self.month > d2.month and self.year == d2.year: returnTrue if self.day > d2.day and d2.month == self.month and \ self.year == d2.year: returnTrue returnFalse

  6. An Elegant Solution def isBefore(self, d2): """ Returns true if self is before d2 """ if self.year < d2.year: returnTrue if self.month < d2.month and self.year == d2.year: returnTrue if self.day < d2.day and d2.month == self.month and \ self.year == d2.year: returnTrue returnFalse def isAfter(self, d2): """ Returns true if self is after d2 """ return d2.isBefore(self)

  7. Another Elegant Solution def isBefore(self, d2): """ Returns true if self is before d2 """ return ([self.year, self.month, self.day] < [d2.year, d2.month, d2.day]) def isAfter(self, d2): """ Returns true if self is after d2 """ return d2.isBefore(self)

  8. diff defdiff( self, d2 ): """ Returns the number of days between self and d2 """ dcopy = self.copy() difference = 0 if dcopy.isBefore(d2) == True: while dcopy.isBefore(d2) == True: dcopy.tomorrow() difference -= 1 else: while dcopy.isAfter(d2): dcopy.yesterday() difference += 1 return difference

  9. An Elegant Solution defdiff( self, d2 ): """ Returns the number of days between self and d2 """ dcopy = self.copy() difference = 0 while dcopy.isBefore(d2): dcopy.tomorrow() difference -= 1 while dcopy.isAfter(d2): dcopy.yesterday() difference += 1 return difference

  10. Aargh! Python has no Connect-four datatype… | | | | | | | | | | | | | | | | | | | | | | | | | | | |X| | | | | |X| |X|O| | | |X|O|O|O|X| |O| --------------- 0 1 2 3 4 5 6 … but we can correct that! Can I see a demo?

  11. Designing classes 1) What data? (Data Members) Not limited to 7x6! 2) What are objects' crucial capabilities? (Methods)

  12. int int Connect Four: the objectb str str str str list width Board b data str str str str height str str str str data What is the name of the method that will construct this data?

  13. Connect Four: constructor class Board: """ a datatype representing a C4 board with an arbitrary number of rows and cols """ def__init__( self, width, height ): """ the constructor for objects of type Board """ self.width = width self.height = height self.data = [] # this will be the board for row in range( 6 ): boardRow = [] for col in range( 7 ): boardRow += [' '] # add a space to this row self.data += [boardRow] Bad magic?

  14. int int Connect Four: the objectb str str str str list width Board b data str str str str height str str str str | | | | | | | | | | | | | | | | | | | | | | | | | | | |X| | | | | |X| |X|O| | | |X|O|O|O|X| |O| --------------- 0 1 2 3 4 5 6 What is the name of the method that will print this data?

  15. Connect Four: __repr__ def__repr__(self): """ this method returns a string representation for an object of type Board """ s = '' for row in range( 6 ): s += '|' for col inrange( 7 ): s += self.data[row][col] + '|' s += '\n' return s which row is row 0, row 1, and so on? To change? To add?

  16. NAME: "Quiz" class Board: defallowsMove(self, col): defaddMove(self, col, ox): for row inrange( self.height ): if self.data[row][col] != ' ': self.data[row-1][col] = ox self.data[self.height-1][col] = ox Write allowsMove to return True if col is a valid move; False otherwise. a C4 board col # 'X' or 'O' Step through this addMove method. What is each line doing? How many problems are there?

  17. C4 Board class: methods __init__( self, width, height ) the “constructor” allowsMove( self, col ) checks if allowed addMove( self, col, ox ) places a checker delMove( self, col ) removes a checker __repr__( self ) outputs a string isFull( self ) checks if any space is left winsFor( self, ox ) checks if a player has won hostGame( self ) play (person vs. person)! Which of these will require the most thought?

  18. winsFor( self, ox ) b b.winsFor( 'X' ) or 'O' X O Thoughts? corner cases?

  19. ? Strategic thinking == intelligence Two-player games have been a key focus of AI as long as computers have been around… In 1945, Alan Turing predicted that computers would be better chess players than people in ~ 50 years… and thus would have achieved intelligence. Alan Turing memorial Manchester, England

  20. ? Strategic thinking == intelligence Two-player games have been a key focus of AI as long as computers have been around… humans computers good at evaluating the strength of a board for a player good at looking ahead in the game to find winning combinations of moves … humans and computers have different relative strengths in these games.

  21. How humans play games… An experiment (by A. deGroot) was performed in which chess positions were shown to novice and expert players… - experts could reconstruct these perfectly - novice players did far worse…

  22. How humans play games… An experiment (by A. deGroot) was performed in which chess positions were shown to novice and expert players… - experts could reconstruct these perfectly - novice players did far worse… Random chess positions (not legal ones) were then shown to the two groups - experts and novices did equally well (badly) at reconstructing them!

  23. ? Strategic thinking == intelligence Two-player games have been a key focus of AI as long as computers have been around… humans computers good at evaluating the strength of a board for a player good at looking ahead in the game to find winning combinations of moves emulating a human by evaluating a board position building an AI chess player … humans and computers have different relative strengths in these games.

  24. The Player class Details Player pForX (data and methods) What data and methods are needed to construct and implement a Player object? Let's see a demo!

  25. Player Picture of a Player object DATA 3 'LEFT' 'X' int ply string tbt string ox Player pForX tiebreakType checker, O or X __init__(self, ox, tbt, ply) __repr__(self) oppCh(self) METHODS scoreBoard(self, b) scoresFor(self, b) tiebreakMove(self, scores) nextMove(self, b)

  26. scoreBoard ‘X’ ‘O’ Assigns a score to any board, b A simple system: 100.0 50.0 0.0 for a win for anything else for a loss Score for Score for Score for Score for

  27. scoreBoard Assigns a score to any board, b A simple system: 0.0 -1.0 100.0 50.0 for a win for a loss illegal board for anything else Implementation ideas… scoreBoard(self, b) This doesn't seem to be looking very far ahead ! What methods that already exist will come in handy? How can there be no 'X' or 'O' input? What class is this method in?

  28. Looking further ahead… scoreBoard looks ahead 0 moves The "Zen" approach -- we are excellent at this! 0-ply If you look one move ahead, how many possibilities are there to consider? A 1-ply lookahead player will "see" an impending victory. to move… 1-ply score A score for each column…?

  29. Looking further ahead… scoreBoard looks ahead 0 moves The "Zen" approach -- we are excellent at this! 0-ply If you look one move ahead, how many possibilities are there to consider? A 2-ply lookahead player will also "see" an opponent's impending victory. to move… 1-ply score 2-ply What about 3-ply? score

  30. Looking further ahead… scoreBoard looks ahead 0 moves The "Zen" approach -- we are excellent at this! 0-ply If you look one move ahead, how many possibilities are there to consider? 1-ply 2-ply scoresFor( self, b ) returns a LIST of scores, one for each column you can choose to move next…

  31. Example 1-ply and 2-ply lookahead scores It is O’s move. What scores does a 1-ply lookahead for O assign to each move? |O| | | | | | | |X| | | |O| |X| |O| | | |X|O|X| |X| | | |O|O|X| |X| |X| |X|O|O| |X| |O|O|O|X|X| --------------- 0 1 2 3 4 5 6 col 0 col 1 col 2 col 3 col 4 col 5 col 6 Which change at 2-ply? It is X’s move. What scores does a 2-ply lookahead for X assign to each move? | | | | | | |O| | | | | | | |O| | | | | | | |X| |X| |X|O| | |O| |X|O|O|X| |X|X| |X|O|O|O| |O|X| --------------- 0 1 2 3 4 5 6 col 0 col 1 col 2 col 3 col 4 col 5 col 6 Which change at 3-ply?

  32. Practice b ‘X’ ‘O’ col 0 col 1 col 2 col 3 col 4 col 5 col 6 0-ply scores for O: col 0 col 1 col 2 col 3 col 4 col 5 col 6 1-ply scores for O: col 0 col 1 col 2 col 3 col 4 col 5 col 6 2-ply scores for O: col 0 col 1 col 2 col 3 col 4 col 5 col 6 3-ply scores for O:

  33. Solutions b ‘X’ ‘O’ col 0 col 1 col 2 col 3 col 4 col 5 col 6 0-ply scores for O: 50 -1 50 50 50 50 50 col 0 col 1 col 2 col 3 col 4 col 5 col 6 1-ply scores for O: -1 50 50 50 50 100 50 col 0 col 1 col 2 col 3 col 4 col 5 col 6 2-ply scores for O: 0 0 -1 0 100 0 50 col 0 col 1 col 2 col 3 col 4 col 5 col 6 3-ply scores for O: 0 0 0 -1 0 100 100

  34. Computer Chess Computers cut their teeth playing chess… Ranking first paper: 1950 beginner early programs ~ 1960’s 500 100’s of moves/sec amateur 1200 10,000’s of moves/sec MacHack (1100) ~ 1967 MIT 1,000,000’s moves/sec world ranked Slate (2070) ~ 1970’s Northwestern 2000 Deep Thought ~ 1989 Carnegie Mellon 3,500,000 moves/sec Deep Blue ~ 1996 IBM Deep Fritz: 2002 X3D Fritz: 2003 Hydra: 2006 What is Hydra's chess rating? world champion 2800 Deep Blue rematch ~ 1997 IBM 200,000,000 moves/sec

  35. Games’ Branching Factors • On average, there are fewer than 40 possible moves that a chess player can make from any board configuration… 0 Ply 1 Ply 2 Ply Branching Factor Estimates for different two-player games Tic-tac-toe 4 Connect Four 7 Checkers 10 Othello 30 Chess 40 Go 300 Hydra at home in the United Arab Emirates… Hydra looks ahead 18 ply !

  36. Games’ Branching Factors 0 Ply 1 Ply 2 Ply Branching Factor Estimates for different two-player games Tic-tac-toe 4 Connect Four 7 Checkers 10 Othello 30 Chess 40 Go 300 Boundaries for qualitatively different games…

  37. Games’ Branching Factors 0 Ply 1 Ply 2 Ply Branching Factor Estimates for different two-player games Progress Tic-tac-toe 4 Connect Four 7 Checkers 10 Othello 30 Chess 40 Go 300 “solved” games computer-dominated human-dominated

  38. ‘X’ scoresFor each column ‘O’ new‘X’ b (1) For each possible move (2) Add it to the board Col 6 Col 0 Col 5 Col 1 Col 2 Col 3 Col 4

  39. ‘X’ scoresFor each column ‘O’ new‘X’ b (1) For each possible move (2) Add it to the board (3) Ask OPPONENT to score each board At what ply? 0.0 50.0 Col 6 Col 0 Col 5 Col 1 Col 2 Col 3 Col 4 50.0 50.0 0.0 0.0 0.0

  40. ‘X’ scoresFor each column ‘O’ new‘X’ b (1) For each possible move (2) Add it to the board (3) Ask OPPONENT to score each board (4) Take the opponent's MAX What to assign for a score? 0.0 50.0 Col 6 Col 0 Col 5 Col 1 Col 2 Col 3 Col 4 50.0 50.0 0.0 0.0 0.0

  41. scoresFor (1) For each possible move (2) Add it to the board (3) Ask OPPONENT to score each board - at ? ply (4) the score is 100-max def scoresFor(self, b):

  42. deftiebreakMove(self, scores): if self.tbt == 'LEFT': Write tiebreakMove to return the leftmost best score inside the list scores How would 'RANDOM' and 'RIGHT'work differently?

  43. hw11 this week http://www.stanford.edu/~ccecka/research/C4.html • Problem 2: A Connect Four Board… • Problem 3: A Connect Four Player… • Extra: scoreBoard4Tourney and a CS 5 C4 round-robin Using more scores than 0, 50, and 100 ! don't give this board a 50.0 !

  44. “Quiz” Names: It is O’s move. What scores does a 1-ply lookahead for O assign to each move? |O| | | | | | | |X| | | |O| |X| |O| | | |X|O|X| |X| | | |O|O|X| |X| |X| |X|O|O| |X| |O|O|O|X|X| --------------- 0 1 2 3 4 5 6 col 0 col 1 col 2 col 3 col 4 col 5 col 6 -1 100 50 100 50 100 50 0 0 Which change at 2-ply? | | | | | | |O| | | | | | | |O| | | | | | | |X| |X| |X|O| | |O| |X|O|O|X| |X|X| |X|O|O|O| |O|X| --------------- 0 1 2 3 4 5 6 It is X’s move. What scores does a 2-ply lookahead for X assign to each move? be careful! col 0 col 1 col 2 col 3 col 4 col 5 col 6 100 0 0 0 0 50 -1 Which change at 3-ply? 0

  45. It is O’s move. What scores does a 1-ply lookahead for O assign to each move? |O| | | | | | | |X| | | |O| |X| |O| | | |X|O|X| |X| | | |O|O|X| |X| |X| |X|O|O| |X| |O|O|O|X|X| --------------- 0 1 2 3 4 5 6 col 0 col 1 col 2 col 3 col 4 col 5 col 6 Which change at 2-ply?

  46. Looking further ahead … Zen choice of move: here and now 0 ply: 1 ply: 2 ply: 3 ply: X’s move X‘s move X’s move | | | | | | | | | | | | | | | | | | | | |X| | | | | | | |O|O| | | |X|X| |X|O| | |O|X|O| |O|X| | --------------- 0 1 2 3 4 5 6 | | | | | | | | | | | | | | | | |O| | | | | | | |X| | | | | | | |X|O|O| | |X| | |O|X|X|O|X|O| | --------------- 0 1 2 3 4 5 6 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |O|X| | | | | |O|X|X|X| |O|O| --------------- 0 1 2 3 4 5 6 (1) Player will win (2) Player will avoid losing (3) Player will set up a win by forcing the opponent to avoid losing

  47. ‘X’ Choosing the best move ‘O’ new‘X’ b (1) For each possible move (2) Add it to the board (3) Ask OPPONENT to score each board - ply? (4) Reverse the scores 100.0 50.0 Col 6 Col 0 Col 5 Col 1 Col 2 Col 3 Col 4 50.0 50.0 100.0 100.0 100.0

  48. ‘X’ Choosing the best move ‘O’ new‘X’ b (1) For each possible move (2) Add it to the board (3) Ask OPPONENT to score each board - ply? (4) Reverse the scores (5) Find one max - that's it! 100.0 50.0 Col 6 Col 0 Col 5 Col 1 Col 2 Col 3 Col 4 50.0 50.0 100.0 100.0 100.0

  49. Connect Four For your convenience, the creators of Python’s library have included a Board class that can represent any size of Connect Four board... ! | | | | | | | | | | | | | | | | | | | | | | | | | | | |X| | | | | |X| |X|O| | | |X|O|O|O|X| |O| --------------- 0 1 2 3 4 5 6 Suppose our Board class's 2d list of lists is named self.data. What is the name of this single spot?

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