Re: First attempt at a Python prog (Chess)
On 2013-02-13 23:25:09 +, Chris Hinsley said:
New to Python, which I really like BTW.
First serious prog. Hope you like it. I know it needs a 'can't move if
your King would be put into check' test. But the weighted value of the
King piece does a surprising emergent job.
New version with better search and hopefully a little better Python. I
know it's still far from fully correct and it'll never best Gary
Kasperov. :)
With pypy on my Macbook I can go to 6 PLY with resonable performance
now due to the alpha-beta pruneing.
Regards
#!/usr/bin/python -tt
# -*- coding: utf-8 -*-
# Copyright (C) 2013 Chris Hinsley, GPL V3 License
import sys
import random
import os
PLY = 5
EMPTY = 0
WHITE = 1
BLACK = -1
NO_CAPTURE = 2
MAY_CAPTURE = 3
MUST_CAPTURE = 4
piece_type = {' ' : EMPTY, 'K' : BLACK, 'Q' : BLACK, 'R' : BLACK, 'B' :
BLACK, 'N' : BLACK, 'P' : BLACK, \
'k' : WHITE, 'q' : WHITE, 'r' : WHITE, 'b' : WHITE, 'n' :
WHITE, 'p' : WHITE}
def display_board(board):
print ' a b c d e f g h'
print '+---+---+---+---+---+---+---+---+'
for row in range(8):
for col in range(8):
print '| %c' % board[row * 8 + col],
print '|', 8 - row
print '+---+---+---+---+---+---+---+---+'
def piece_moves(board, index, dx, dy, capture_flag, distance):
piece = board[index]
type = piece_type[piece]
cy, cx = divmod(index, 8)
for step in range(distance):
nx = cx + (dx * (step + 1))
ny = cy + (dy * (step + 1))
if (0 <= nx < 8) and (0 <= ny < 8):
newindex = ny * 8 + nx
newpiece = board[newindex]
newtype = piece_type[newpiece]
if capture_flag == MUST_CAPTURE:
if newtype != EMPTY and newtype != type:
board[index] = ' '
if (ny == 0 or ny == 7) and piece in 'Pp':
for promote in 'QRBN' if type == BLACK else 'qrbn':
board[newindex] = promote
yield board
else:
board[newindex] = piece
yield board
board[index], board[newindex] = piece, newpiece
elif capture_flag == MAY_CAPTURE:
if newtype == EMPTY:
board[index], board[newindex] = ' ', piece
yield board
board[index], board[newindex] = piece, newpiece
elif newtype != type:
board[index], board[newindex] = ' ', piece
yield board
board[index], board[newindex] = piece, newpiece
break
else:
break
elif newtype == EMPTY:
board[index] = ' '
if (ny == 0 or ny == 7) and piece in 'Pp':
for promote in 'QRBN' if type == BLACK else 'qrbn':
board[newindex] = promote
yield board
else:
board[newindex] = piece
yield board
board[index], board[newindex] = piece, newpiece
else:
break
else:
break
def pawn_moves(board, index, options):
for x, y, flag, distance in options:
for new_board in piece_moves(board, index, x, y, flag, distance):
yield new_board
def other_moves(board, index, options, distance):
for x, y in options:
for new_board in piece_moves(board, index, x, y, MAY_CAPTURE,
distance):
yield new_board
def black_pawn_moves(board, index):
distance = 2 if index in range(8, 16) else 1
for new_board in pawn_moves(board, index, [(0, 1, NO_CAPTURE,
distance), (-1, 1, MUST_CAPTURE, 1), (1, 1, MUST_CAPTURE, 1)]):
yield new_board
def white_pawn_moves(board, index):
distance = 2 if index in range(48, 56) else 1
for new_board in pawn_moves(board, index, [(0, -1, NO_CAPTURE,
distance), (-1, -1, MUST_CAPTURE, 1), (1, -1, MUST_CAPTURE, 1)]):
yield new_board
def rook_moves(board, index):
for new_board in other_moves(board, index, [(0, -1), (-1, 0), (0,
1), (1, 0)], 7):
yield new_board
def bishop_moves(board, index):
for new_board in other_moves(board, index, [(-1, -1), (-1, 1), (1,
1), (1, -1)], 7):
yield new_board
def knight_moves(board, index):
for new_board in other_moves(board, index, [(-2, 1), (2, -1), (2,
1), (-1, -2), (-1, 2), (1, -2), (1, 2)], 1):
yield new_board
def queen_moves(board, index):
for new_board in bishop_moves(board, index):
yield new_board
for new_board in rook_moves(board, index)
Re: odd behavoiur seen
On 2013-07-22 18:36:41 +, Chris Hinsley said:
Folks, I have this decorator:
def memoize(maxsize):
def _memoize(func):
lru_cache = {}
lru_list = []
Other clues, I use it on a recursive function:
@memoize(64)
def next_move(board, colour, alpha, beta, ply):
if ply <= 0:
return evaluate(board) * colour
for new_board in all_moves(board[:], colour):
score = -next_move(new_board, -colour, -beta, -alpha, ply - 1)
if score >= beta:
return score
if score > alpha:
alpha = score
return alpha
And I notice I don't get the strange problem on a non-recursive
function ! Or at least I don't seam to.
Chris
--
http://mail.python.org/mailman/listinfo/python-list
odd behavoiur seen
Folks, I have this decorator:
def memoize(maxsize):
def _memoize(func):
lru_cache = {}
lru_list = []
def memoizer(*args, **kwargs):
key = str(args) + str(kwargs)
if key in lru_cache:
lru_list.remove(key)
lru_list.append(key)
return lru_cache[key]
print len(lru_list),
if len(lru_list) >= maxsize:
del(lru_cache[lru_list[0]])
del(lru_list[0])
ret = func(*args, **kwargs)
lru_cache[key] = ret
lru_list.append(key)
return ret
return memoizer
return _memoize
I didn't used to do the 'len(lru_list) >= maxsize' just '==' and
noticed it sailing past the max number of entries, so put in the print
statement, and now I see it ocationally printing a value 1 larger than
maxsize !!!
So if I use it as '@memoize(64)' I see some 65's in the output ! I'm at
a loss to explain it, does anyone knows why ? Is it a bug or some
threading issue ? I'm not useing threads BTW, and I've noticed this in
both running it with Python or Pypy.
Best Regards
Chris
--
http://mail.python.org/mailman/listinfo/python-list
Re: odd behavoiur seen
On 2013-07-22 19:47:33 +, Peter Otten said:
Chris Hinsley wrote:
On 2013-07-22 18:36:41 +, Chris Hinsley said:
Folks, I have this decorator:
def memoize(maxsize):
def _memoize(func):
lru_cache = {}
lru_list = []
Other clues, I use it on a recursive function:
@memoize(64)
def next_move(board, colour, alpha, beta, ply):
if ply <= 0:
return evaluate(board) * colour
for new_board in all_moves(board[:], colour):
score = -next_move(new_board, -colour, -beta, -alpha, ply - 1)
if score >= beta:
return score
if score > alpha:
alpha = score
return alpha
And I notice I don't get the strange problem on a non-recursive
function ! Or at least I don't seam to.
That's indeed the problem:
if len(lru_list) >= maxsize:
del(lru_cache[lru_list[0]])
del(lru_list[0])
ret = func(*args, **kwargs)
lru_cache[key] = ret
lru_list.append(key)
You delete a cached item, then call the original function which causes calls
of the decorated function. This causes a length check which sees the already
reduced length and decides that the cache is not yet full.
If you remove the oldest item after calling the original function you should
be OK.
Ah ! Thank you kindly sir !
Chris
--
http://mail.python.org/mailman/listinfo/python-list
New github source
Hellow, just letting people know I've put up some github repo's of my Pthon projects: https://github.com/vygr/Python-PCB https://github.com/vygr/Python-Chess Regards Chris -- https://mail.python.org/mailman/listinfo/python-list
Re: First attempt at a Python prog (Chess)
On 2013-02-15 05:05:27 +, Rick Johnson said:
On Thursday, February 14, 2013 11:48:10 AM UTC-6, Chris Hinsley wrote:
Is a Python list as fast as a bytearray?
Why would you care about that now? Are you running this code on the
Xerox Alto? Excuse me for the sarcasm but your post title has perplexed
me:
"First attempt at a Python prog (Chess)"Okay, but how does that translate to:
"The fastest, most efficient, most brain fricked python code ever
released in the form of a game, that just happens to look an awful lot
like C source"?
http://en.wikipedia.org/wiki/Optimization_%28computer_science%29#When_to_optimize
Why bother to use Python if what you really want to write is C code? If
you want to write good code (not just python), you need to write code
that is maintainable. Yes i KNOW, this is just some stupid chess game,
but i can assure you that this style of code is only going to harm your
evolution. This code is obfuscated at best and BF'ed at worst. And
forget about the algorithms for now, the first problems to address are
superficial.
First of all your naming conventions suck. You've used the "interface"
style for every function in this game so i can't /easily/ eyeball parse
the /real/ interface functions from the helper functions -- and i'm not
going to even try, because i don't read ugly code! Try to learn the
Python style guide as soon as you can (In particular pay attention to
naming conventions):
http://www.python.org/dev/peps/pep-0008/
Secondly this game could benefit from some OOP paradigm (not sure if
are familiar with OOP or not???). But don't go bat-crazy with OOP! You
don't need an object to represent /every/ single piece on the board
(That would be nuts!). You need just enough OOP to encapsulate the data
and create a proper interface.
A good litmus test is based on the "three little bears":
"Papa bears bed is too hard"
A hard utilization of paradigms wields too little OOP and therefore
ends up being too difficult (aka: "hard") to maintain because there is
no logical interface; just a massive collection of functions stuffed
into global space until BF reaches critical mass and you're forced to
do a complete re-write! (Of course sometimes you don't need OOP at all,
just interface)
"Mama bears bed is too soft"
A soft utilization of paradigms wields too much OOP whereby you are
surrounded by big FAT objects which are smothering you to death, and
they smell because they cannot properly wash themselves between the
rolls of fat.
"but baby bears is just right"
Ahhh, the blissful comfort of a paradigm utilization that is "just
right". This is where your code should be, you want a level of OOP
usage that is "just right" for the occasion; not any more, not any less.
## START EXAMPLE CODE ##
class GameBoard(???):
def __init__(self):
self.board = self._createBoard()
def __str__(self):
"""Override:"""
# return a string represention of the board
# suitable for writing to stdout
def _createBoard(self):
"""Internal:"""
self.board = [blah]
def make_move(self, piece, vector):
"""Interface: move a game piece based on vector"""
# Find and move the piece. Whether the pieces
# are objects or not doesn't matter.
class GamePiece(object):
def __init__(self, typename, color):
self.typeName = typeName
self.color = color
self.captureFlag = self._computeFlag()
def main():
board = Board()
playing = True
while playing is not False
i = input('PieceName - MoveVec:')
n, v = parse(i)
result = board.make_move(n, v)
if result == 'GameOver':
playing = False
else:
# clear the stdout
str(board)
if __name__ == '__main__:
main()
## END EXAMPLE CODE ##
And now you have the added benefit of exporting the objects for use elsewhere.
Wow, such vitriol for such a simple bear to cope with !
Maybe Papa bear would like to try some humility !
This was my very first Python prog, and my first chess prog and my
attempt to learn somthing about Generators ! Do youtself a favour and
leave the Python comunity for the good of the language !
Chris
--
https://mail.python.org/mailman/listinfo/python-list
Latest Chess prog
Latest version of Chess test prog for anyone who might be interested.
It does not do en-passon or castling.
Best Regards
Chris
#!/opt/local/bin/pypy -u -tt
#!/opt/local/bin/pypy -u -tt -m cProfile
# -*- coding: utf-8 -*-
# Copyright (C) 2013-2014 Chris Hinsley, GPL V3 License
import sys, os, time
from operator import itemgetter
from array import array
MAX_PLY = 10
MAX_TIME_PER_MOVE = 10
PIECE_VALUE_FACTOR = 3
KING_VALUE, QUEEN_VALUE, ROOK_VALUE = 100, 9 * PIECE_VALUE_FACTOR,
5 * PIECE_VALUE_FACTOR
BISHOP_VALUE, KNIGHT_VALUE, PAWN_VALUE = 3 * PIECE_VALUE_FACTOR, 3 *
PIECE_VALUE_FACTOR, 1 * PIECE_VALUE_FACTOR
EMPTY, WHITE, BLACK = 0, 1, -1
NO_CAPTURE, MAY_CAPTURE, MUST_CAPTURE = 0, 1, 2
piece_type = {' ' : EMPTY, 'K' : BLACK, 'Q' : BLACK, 'R' : BLACK, 'B' :
BLACK, 'N' : BLACK, 'P' : BLACK, \
'k' : WHITE, 'q' : WHITE, 'r' : WHITE, 'b' : WHITE, 'n' : WHITE, 'p'
: WHITE}
def display_board(board):
print
print ' a b c d e f g h'
print '+---+---+---+---+---+---+---+---+'
for row in range(8):
for col in range(8):
print '| %c' % board[row * 8 + col],
print '|', 8 - row
print '+---+---+---+---+---+---+---+---+'
print
def piece_moves(board, index, vectors):
piece = board[index]
type = piece_type[piece]
promote = 'QRBN' if type == BLACK else 'qrbn'
cy, cx = divmod(index, 8)
for dx, dy, length, flag in vectors:
x, y = cx, cy
if length == 0:
if piece == 'P':
length = 2 if (y == 1) else 1
else:
length = 2 if (y == 6) else 1
while length > 0:
x += dx; y += dy; length -= 1
if (x < 0) or (x >=8) or (y < 0) or (y >= 8):
break
newindex = y * 8 + x
newpiece = board[newindex]
newtype = piece_type[newpiece]
if newtype == type:
break
if (flag == NO_CAPTURE) and (newtype != EMPTY):
break
if (flag == MUST_CAPTURE) and (newtype == EMPTY):
break
board[index] = ' '
if (y == 0 or y == 7) and piece in 'Pp':
for promote_piece in promote:
board[newindex] = promote_piece
yield board
else:
board[newindex] = piece
yield board
board[index], board[newindex] = piece, newpiece
if (flag == MAY_CAPTURE) and (newtype != EMPTY):
break
def piece_scans(board, index, vectors):
cy, cx = divmod(index, 8)
for dx, dy, length in vectors:
x, y = cx, cy
while length > 0:
x += dx; y += dy; length -= 1
if (0 <= x < 8) and (0 <= y < 8):
piece = board[y * 8 + x]
if piece != ' ':
yield piece
break
black_pawn_vectors = [(-1, 1, 1), (1, 1, 1)]
white_pawn_vectors = [(-1, -1, 1), (1, -1, 1)]
bishop_vectors = [(x, y, 7) for x, y in [(-1, -1), (1, 1), (-1, 1), (1, -1)]]
rook_vectors = [(x, y, 7) for x, y in [(0, -1), (-1, 0), (0, 1), (1, 0)]]
knight_vectors = [(x, y, 1) for x, y in [(-2, 1), (2, -1), (2, 1), (-2,
-1), (-1, -2), (-1, 2), (1, -2), (1, 2)]]
queen_vectors = bishop_vectors + rook_vectors
king_vectors = [(x, y, 1) for x, y, _ in queen_vectors]
black_pawn_moves = [(0, 1, 0, NO_CAPTURE), (-1, 1, 1, MUST_CAPTURE),
(1, 1, 1, MUST_CAPTURE)]
white_pawn_moves = [(x, -1, length, flag) for x, _, length, flag in
black_pawn_moves]
rook_moves = [(x, y, length, MAY_CAPTURE) for x, y, length in rook_vectors]
bishop_moves = [(x, y, length, MAY_CAPTURE) for x, y, length in bishop_vectors]
knight_moves = [(x, y, length, MAY_CAPTURE) for x, y, length in knight_vectors]
queen_moves = bishop_moves + rook_moves
king_moves = [(x, y, 1, flag) for x, y, _, flag in queen_moves]
moves = {'P' : black_pawn_moves, 'p' : white_pawn_moves, 'R' :
rook_moves, 'r' : rook_moves, \
'B' : bishop_moves, 'b' : bishop_moves, 'N' : knigh
First attempt at a Python prog (Chess)
New to Python, which I really like BTW.
First serious prog. Hope you like it. I know it needs a 'can't move if
your King would be put into check' test. But the weighted value of the
King piece does a surprising emergent job.
#!/usr/bin/python -tt
# -*- coding: utf-8 -*-
# Copyright (C) 2013 Chris Hinsley, GPL V3 License
import sys
import random
import os
PLY = 3
EMPTY = 0
BLACK = 1
WHITE = 2
NO_CAPTURE = 3
MAY_CAPTURE = 4
MUST_CAPTURE = 5
def piece_type(piece):
return EMPTY if piece == 32 else BLACK if chr(piece) in 'KQRBNP' else WHITE
def display_board(board):
print ' a b c d e f g h'
print '+---+---+---+---+---+---+---+---+'
for row in range(8):
for col in range(8):
sys.stdout.write('| ')
sys.stdout.write(chr(board[row * 8 + col]))
sys.stdout.write(' ')
sys.stdout.write('|')
print 8 - row
print '+---+---+---+---+---+---+---+---+'
def piece_moves(board, index, dx, dy, capture_flag, distance):
piece = board[index]
type = piece_type(piece)
cx = index % 8
cy = index / 8
for step in range(distance):
nx = cx + (dx * (step + 1))
ny = cy + (dy * (step + 1))
if nx in range(8) and ny in range(8):
newindex = ny * 8 + nx
newpiece = board[newindex]
newtype = piece_type(newpiece)
if capture_flag == MUST_CAPTURE:
if newtype != EMPTY and newtype != type:
board[index] = ' '
if (ny == 0 or ny == 7) and chr(piece) in 'Pp':
for promote in 'QRBN' if type == BLACK else 'qrbn':
board[newindex] = promote
yield board
else:
board[newindex] = piece
yield board
board[index], board[newindex] = piece, newpiece
elif capture_flag == MAY_CAPTURE:
if newtype == EMPTY or newtype != type:
board[index], board[newindex] = ' ', piece
yield board
board[index], board[newindex] = piece, newpiece
break
elif newtype == EMPTY:
board[index] = ' '
if (ny == 0 or ny == 7) and chr(piece) in 'Pp':
for promote in 'QRBN' if type == BLACK else 'qrbn':
board[newindex] = promote
yield board
else:
board[newindex] = piece
yield board
board[index], board[newindex] = piece, newpiece
else:
break
def pawn_moves(board, index, options):
for x, y, flag, distance in options:
for new_board in piece_moves(board, index, x, y, flag, distance):
yield new_board
def other_moves(board, index, options, distance):
for x, y in options:
for new_board in piece_moves(board, index, x, y, MAY_CAPTURE,
distance):
yield new_board
def black_pawn_moves(board, index):
distance = 2 if index in range(8, 16) else 1
for new_board in pawn_moves(board, index, [(0, 1, NO_CAPTURE,
distance), (-1, 1, MUST_CAPTURE, 1), (1, 1, MUST_CAPTURE, 1)]):
yield new_board
def white_pawn_moves(board, index):
distance = 2 if index in range(48, 56) else 1
for new_board in pawn_moves(board, index, [(0, -1, NO_CAPTURE,
distance), (-1, -1, MUST_CAPTURE, 1), (1, -1, MUST_CAPTURE, 1)]):
yield new_board
def rook_moves(board, index):
for new_board in other_moves(board, index, [(0, -1), (-1, 0), (0,
1), (1, 0)], 7):
yield new_board
def bishop_moves(board, index):
for new_board in other_moves(board, index, [(-1, -1), (-1, 1), (1,
1), (1, -1)], 7):
yield new_board
def knight_moves(board, index):
for new_board in other_moves(board, index, [(-2, 1), (2, -1), (2,
1), (-1, -2), (-1, 2), (1, -2), (1, 2)], 1):
yield new_board
def queen_moves(board, index):
for new_board in bishop_moves(board, index):
yield new_board
for new_board in rook_moves(board, index):
yield new_board
def king_moves(board, index):
for new_board in other_moves(board, index, [(0, -1), (-1, 0), (0,
1), (1, 0), (-1, -1), (-1, 1), (1, 1), (1, -1)], 1):
yield new_board
moves = {'P' : black_pawn_moves, 'p' : white_pawn_moves, \
'R' : rook_moves, 'r' : rook_moves, \
'B' : bishop_moves, 'b' : bishop_moves, \
'N' : knight_moves, 'n' : knight_moves, \
'Q' : queen_moves, 'q' : queen_moves, \
'K' : king_moves, 'k' : king_moves}
def all_moves(board, turn):
for index, piece in enumerate(board):
if piece_type(pi
Re: First attempt at a Python prog (Chess)
On 2013-02-13 23:55:20 +, Oscar Benjamin said: On 13 February 2013 23:25, Chris Hinsley wrote: New to Python, which I really like BTW. Glad to hear it. First serious prog. Hope you like it. I know it needs a 'can't move if your King would be put into check' test. But the weighted value of the King piece does a surprising emergent job. [SNIP program] Your program looks good. Were you looking for feedback (I'm sure someone would give some if so)? Oscar I suppose so yes. I was just 'putting it out there' to see if it was interesting/useful to anyone. No doubt there are many Python features I could use to improve on this. First thing that occurred to me on deciding to try Python was the idea of Generator functions to enumerate all the possible moves of a Chess game, and that 'yield' would make the prog relatively compact. I wish Shedskin could cope with them ! PyPy runs it OK. Chris -- http://mail.python.org/mailman/listinfo/python-list
Re: First attempt at a Python prog (Chess)
On 2013-02-14 06:05:13 +, Tim Roberts said: Chris Hinsley wrote: New to Python, which I really like BTW. First serious prog. Hope you like it. I know it needs a 'can't move if your King would be put into check' test. But the weighted value of the King piece does a surprising emergent job. It looks a little like a C program ported line-by-line to Python. For example, in Python, there's no reason not to keep the board as an 8x8 array instead of a 64-element list. That by itself would make the code easier to read. It would also let you replace this: for row in range(8): for col in range(8): with the more Pythonic: for row in board: for cell in row: I would probably replace the piece_type function with a map that maps the piece number directly to the piece Is a Python list as fast as a bytearray ? I didn't copy a C prog BTW ! Yep, after I posted the code I started thinking about how to do that sort of thing :) Thanks, for the advice. Chris -- http://mail.python.org/mailman/listinfo/python-list
Re: First attempt at a Python prog (Chess)
On 2013-02-14 21:14:03 +, jkn said: Hi Chris On Wednesday, 13 February 2013 23:25:09 UTC, Chris Hinsley wrote: New to Python, which I really like BTW. Welcome aboard! But aren't you supposed to be writing Forth? ;-) Cheers Jon N Well, I'm experimenting with other things too ! :) I might yet even have another bash at Lisp... Chris -- http://mail.python.org/mailman/listinfo/python-list
