IS313 Tomorrow… Wednesday, Nov Classes + Objects, part 2 Wednesday, Nov Classes + Objects, part 3 Thursday, Nov Date class due Thursday, Nov Board class due & proposal Wednesday, Dec. 2 - Networks and their analysis Thursday, Dec. 3 - progress report due – with code Wednesday, Dec. 9 - In-class project presentations Thursday, Dec progress report due – with code Wednesday, Dec no class meeting Thursday, Dec Final project due! HMC news… Wednesday, Dec Player class due (Hw #9) IS 313 Schedule

IS313 today: Intelligent software 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 to move. Is there a way to win? | | | | | | | |X| | | | | |X| |X|O| | | |X|O|O|O|X|O| | import antigravity!

Aargh! Python has no Connect-four datatype… | | | | | | | |X| | | | | |X| |X|O| | | |X|O|O|O|X|O| | Can I see a demo? … but we can correct that!

Designing classes 1) What data? (Data Members) 2) What are the key capabilities? (Methods) Not limited to 7x6!

Connect Four: the object b Board b int width str data list str ? int height What is the name of the method that will construct this data? Starting from b, how would you examine the string marked by the ? 3 4

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 self.data = [ [' ']*self.width ] * self.height Doesn't work! Not much of a game…

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( self.width ): boardRow = [] for col in range( self.height ): boardRow += [' '] # add a space to this row self.data += [boardRow] Better! Same idea as in Life

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 self.data = [ [' ']*self.width for row in range(self.height) ] Even shorter! What was this called again… ?

Connect Four: the object b Board b int width str data list str int height | | | | | | | |X| | | | | |X| |X|O| | | |X|O|O|O|X| |O| X O O O XX X … … … … printed version Which rows and columns are these? which is row 0 ? …

The grim task of printing … Board b int width str data list str int height | | | | | | | |X| | | | | |X| |X|O| | | |X|O|O|O|X| |O| What is the name of the method that will print this data? 6 7 X O O O XX X … … … … Which rows and columns are these?

def __repr__(self): """ this method returns a string representation for an object of type Board """ s = '' for row in range( self.height ): s += '|' for col in range( self.width ): s += self.data[row][col] + '|' s += '\n' return s Connect Four: __repr__ What else?

>>> b = Board( 7, 6 ) >>> print b >>> LoS = [ ' ', ' ', 'OXO ', 'XXOO ', 'XOXXOX ', 'XOOXXOO' ] >>> b.set_board( LoS ) >>> print b Connect Four: set_board | | | | |O|X|O| | | | | |X|X|O|O| | | | |X|O|X|X|O|X| | |X|O|O|X|X|O|O| | | | | What is this a list of?

def set_board(self, LoS): """ this method sets the board to the list_of_strings that is input """ for row in range( ): for col in range( ): self.data[row][col] = LoS[row][col] Connect Four: set_board What goes in the blanks?

Try it! def addMove(self, col, ox): row = self.height-1 while True: if self.data[row][col] == ' ': self.data[row][col] = ox row -= 1 Step through this addMove method. How does it work? What's wrong? Try to fix it… ! a C4 board col # 'O' or 'X' | | | | |O|X|O| | | | | |X|X|O|O| | | | |X|O|X|X|O|X| | |X|O|O|X|X|O|O|

Try it! def allowsMove(self, col): a C4 board col # allowsMove should return True if col has enough space to allow a move; it should return False otherwise. | |X| | | | | | | |O| | | | | | |O|X|O| | | | | |X|X|O|O| | | | |X|O|X|X|O|X| | |X|O|O|X|X|O|O| b b.allowsMove(0) b.allowsMove(1) True False

C4 Board class: methods __init__( self, width, height ) allowsMove( self, col ) __repr__( self ) addMove( self, col, ox ) isFull( self ) winsFor( self, ox ) the “constructor” checks if allowed places a checker outputs a string checks if any space is left checks if a player has won hostGame( self ) play! delMove( self, col ) removes a checker What will require the most thought? set_board( self, LoS ) sets the board arbitrarily

Checking wins… ? Thoughts? X O self corner cases?

Two-player games have been a key focus of AI as long as computers have been around… Strategic thinking == intelligence ? 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

Two-player games have been a key focus of AI as long as computers have been around… Strategic thinking == intelligence ? … humans and computers have different relative strengths in these games. 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

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

How humans play games… - 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! An experiment (by A. deGroot) was performed in which chess positions were shown to novice and expert players…

Two-player games have been a key focus of AI as long as computers have been around… Strategic thinking == intelligence ? 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. hw9 pr1 building an AI chess player

Player class Player pForX What data does an AI player need? Let's see a demo! string ox string tbt 'X' 'LEFT' int ply 0 DATA MEMBERS tiebreakTypechecker, O or Xmoves to look ahead surprisingly little! How about knowledge about its opponent?

Player Board and Player methods __init__(self, ox, tbt, ply) __repr__(self) scoreBoard(self, b) scoresFor(self, b) tiebreakMove(self, scores) nextMove(self, b) oppCh(self) Board __init__( self, width, height ) allowsMove( self, col ) __repr__( self ) addMove( self, col, ox ) isFull( self ) winsFor( self, ox ) hostGame( self ) delMove( self, col ) set_board( self, LoS ) Board's data also includes data! All of Player's data

scoreBoard ‘X’ ‘O’ Assigns a score to any board, b A simple system: for a win for a lossfor anything else Score for

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

Looking further ahead… scoreBoard looks ahead 0 moves The "Zen" approach -- we are excellent at this! If you look one move ahead, how many possibilities are there to consider? 0-ply 1-ply A 1-ply lookahead player will "see" an impending victory. to move… A score for each column…? scores p42.scoresFor( b42 ) special case

Looking further ahead… scoreBoard looks ahead 0 moves The "Zen" approach -- we are excellent at this! If you look one move ahead, how many possibilities are there to consider? 0-ply A 2-ply lookahead player will also "see" an opponent's impending victory. to move… What about 3-ply? 2-ply 1-ply score p43.scoresFor( b42 ) and p44

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

self 0-ply scores for O: col 0col 1col 2col 3col 4col 5col 6 1-ply scores for O: col 0col 1col 2col 3col 4col 5col 6 2-ply scores for O: col 0col 1col 2col 3col 4col 5col 6 3-ply scores for O: col 0col 1col 2col 3col 4col 5col 6 Score! ‘X’ ‘O’

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

|O| | | | | | | |X| | | |O| |X| |O| | | |X|O|X| |X| | | |O|O|X| |X| |X| |X|O|O| |X| |O|O|O|X|X| | | | | | | |O| | | | | | | |X| |X| |X|O| | |O| |X|O|O|X| |X|X| |X|O|O|O| |O|X| It is O’s move. What scores does a 1-ply lookahead for O assign to each move? col 0col 1col 2col 3col 4col 5col 6 It is X’s move. What scores does a 2-ply lookahead for X assign to each move? col 0col 1col 2col 3col 4col 5col 6 be careful! Which change at 2-ply? 00 Which change at 3-ply? 0 Answers to example lookahead scores

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

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

‘X’ ‘O’ new‘X’ Col 6 Col 5 Col 4 Col 3 Col 2 Col 1 Col 0 (1) For each possible move (2) Add it to the board (3) Ask OPPONENT to score each board (4) Which score will the opponent choose? What, then, should assign for your score? ( self 's score) scoresFor each column 50.0 self

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

Games’ Branching Factors Branching Factor Estimates for different two-player games Tic-tac-toe 4 Connect Four 7 Checkers 10 Othello 30 Chess 40 Go 300 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 Hydra at home in the United Arab Emirates… Hydra looks ahead 18 ply !

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

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

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

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

Hwks and Projects Homework 9: A Connect Four Player … Homework 8: A Connect Four Board … due 11/19/09 due 12/23/09 ! by the end of the term…

Hwks and Projects Homework 9: A Connect Four Player … Homework 8: A Connect Four Board … due 11/19/09 due 12/23/09 ! by the end of the term… Homework 8, part 2: final project proposal Pre-planned projectsIdeasOpen-ended 4) robot navigation: pyRobot 2) 3d simulation game: vPool 1) Web-based Text Clouds 3) implementing Picobot! Flash Cards ? pySQL ? Image processing using pyGame: "snake" others welcome!

Project Deliverables Proposal due 11/19/09 Preliminary milestone due 12/3/09 one-page ( proposal.txt ) that includes your project choice and a first description of the project-specific ideas - also, what libraries you'll use Working code ( preliminary.zip ) that uses your libraries and shows access to the data you need (sound, graphics, etc.) Also, a plan for the next steps to take -- this may include classes you'll build. Presentation / intermediate milestone due 12/9-10/09 The presentation is ~10 minutes of your vision, the technical details, and a demo of what you have so far. The intermediate.zip milestone should have the presentation, demo, and a final plan, including classes. Project due 12/17/09 Your final project ( project.zip ), with documentation and "future work."

Examples?! Date, due Date(11,11,09).tomorrow()

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

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

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

‘X’ ‘O’ new‘X’ Col 6 Col 5 Col 4 Col 3 Col 2 Col 1 Col 0 b Choosing the best move (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!

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

Connect Four: the object b This is true for sufficiently broad definitions of “the creators of Python’s library”... Board b def addMove(self, col, player) int NROWS int NCOLS def allowsMove(self, col) char data list char def winsFor(self, player) data members methods What is player ?

Connect Four: the object b This is true for sufficiently broad definitions of “the creators of Python’s library”... Board b def addMove(self, col, player) int NROWS int NCOLS def allowsMove(self, col) char data list char def winsFor(self, player) data members methods Which methods will alter b ? Which leave it alone?

Connect Four: Board Starting code for the Board class class Board: def __init__( self, numRows, numCols ): """ our Board's constructor """ self.NROWS = numRows self.NCOLS = numCols self.data = [] for r in range(self.NROWS): onerow = [' ']*self.NCOLS self.data += [onerow] def __repr__(self): """ thoughts? """ look familiar?

Connect Four: Board class Board: def __init__( self, numRows, numCols ): """ our Board's constructor """ self.NROWS = numRows self.NCOLS = numCols self.data = [] for r in range(self.NR): onerow = [' ']*self.NC self.data += [onerow] def __repr__(self): """ thoughts? """ s = '\n' for r in range(self.NROWS): s += '|' for c in range(self.NCOLS): s += self.data[r][c] + '|' return s look familiar? a bit more to go !

Problem 2 class Board __init__ allowsMove __repr__ addMove isFull winsFor the “constructor” checks if allowed places a checker outputs to screen checks if space left checks if a player has won Hw11 Pr2: Connect Four Board hostGame play! What's trickiest here?

Problem 2 class Board __init__ allowsMove __repr__ addMove isFull winsFor the “constructor” checks if allowed places a checker outputs to screen checks if space left checks if a player has won Hw11 Pr2: Connect Four Board hostGame play! What's trickiest here?

What's wrong here? | | | | | | | |O|O| | | |X|X| |O|X|X|X| |X|O|O|O|O|X|X| def winsForHoriz(self, player): inarow = 0 for r in range(self.NROWS): for c in range(self.NCOLS): if self.data[r][c] == player: inarow += 1 else: inarow = 0 if inarow == 4: return True return False

Strategies? horizontals verticals diagonals ?? | | | | | | | |O|O| | | |X|X| |O|X|X|X| |X|O|O|O|O|X|X|

“Quiz” class Board { # __init__ and __repr__ methods here… # 3 data members: # self.NR == number of rows # self.NC == number of cols # self.data == the 2d list of lists of chars def mysteryMethod(self, col, ox): r = 0 while r < self.NR and self.data[r][col] == ' ': r += 1 self.data[r-1][col] = ox def allowsMove(self, col): } Briefly, what is each line of the mysteryMethod doing? Which method is it? Write allowsMove to return whether the input col is a valid column to move. ( True or False ) Could it go wrong?

Problem 2 class Board __init__ allowsMove __repr__ addMove isFull winsFor the “constructor” checks if allowed places a checker outputs to screen checks if space left checks if a player has won Hw11 Pr2: Connect Four Board hostGame play! What's trickiest here?

Problem 2 class Board __init__ allowsMove __repr__ addMove isFull winsFor the “constructor” checks if allowed places a checker outputs to screen checks if space left checks if a player has won Hw11 Pr2: Connect Four Board hostGame play! What's trickiest here?

Strategies? horizontals verticals diagonals ?? | | | | | | | |X| | | | | |X| |X|O| | | |X|O|O|O|O| |O|

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

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