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Copy pathkata_board.py
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1436 lines (1214 loc) · 58.7 KB
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import sys
import random
import numpy as np
class IllegalMoveError(ValueError):
pass
# Implements legal moves without superko
class Board:
EMPTY = 0
BLACK = 1
WHITE = 2
WALL = 3
ZOBRIST_STONE = [[], [], [], []]
ZOBRIST_PLA = []
ZOBRIST_RAND = random.Random()
ZOBRIST_RAND.seed(123987456)
PASS_LOC = 0
for i in range((19 + 1) * (19 + 2) + 1):
ZOBRIST_STONE[BLACK].append(ZOBRIST_RAND.getrandbits(64))
ZOBRIST_STONE[WHITE].append(ZOBRIST_RAND.getrandbits(64))
for i in range(4):
ZOBRIST_PLA.append(ZOBRIST_RAND.getrandbits(64))
def __init__(self, size, copy_other=None):
if size < 2 or size > 39:
raise ValueError("Invalid board size: " + str(size))
self.size = size
self.arrsize = (size + 1) * (size + 2) + 1
self.dy = size + 1
self.adj = [-self.dy, -1, 1, self.dy]
self.diag = [-self.dy - 1, -self.dy + 1, self.dy - 1, self.dy + 1]
if copy_other is not None:
self.pla = copy_other.pla
self.board = np.copy(copy_other.board)
self.group_head = np.copy(copy_other.group_head)
self.group_stone_count = np.copy(copy_other.group_stone_count)
self.group_liberty_count = np.copy(copy_other.group_liberty_count)
self.group_next = np.copy(copy_other.group_next)
self.group_prev = np.copy(copy_other.group_prev)
self.zobrist = copy_other.zobrist
self.simple_ko_point = copy_other.simple_ko_point
else:
self.pla = Board.BLACK
self.board = np.zeros(shape=(self.arrsize), dtype=np.int8)
self.group_head = np.zeros(shape=(self.arrsize), dtype=np.int16)
self.group_stone_count = np.zeros(shape=(self.arrsize), dtype=np.int16)
self.group_liberty_count = np.zeros(shape=(self.arrsize), dtype=np.int16)
self.group_next = np.zeros(shape=(self.arrsize), dtype=np.int16)
self.group_prev = np.zeros(shape=(self.arrsize), dtype=np.int16)
self.zobrist = 0
self.simple_ko_point = None
for i in range(-1, size + 1):
self.board[self.loc(i, -1)] = Board.WALL
self.board[self.loc(i, size)] = Board.WALL
self.board[self.loc(-1, i)] = Board.WALL
self.board[self.loc(size, i)] = Board.WALL
# More-easily catch errors
self.group_head[0] = -1
self.group_next[0] = -1
self.group_prev[0] = -1
def copy(self):
return Board(self.size, copy_other=self)
@staticmethod
def get_opp(pla):
return 3 - pla
@staticmethod
def loc_static(x, y, size):
return (x + 1) + (size + 1) * (y + 1)
def loc(self, x, y):
return (x + 1) + self.dy * (y + 1)
def loc_x(self, loc):
return (loc % self.dy) - 1
def loc_y(self, loc):
return (loc // self.dy) - 1
def is_adjacent(self, loc1, loc2):
return loc1 == loc2 + self.adj[0] or loc1 == loc2 + self.adj[1] or loc1 == loc2 + self.adj[2] or loc1 == loc2 + \
self.adj[3]
def pos_zobrist(self):
return self.zobrist
def sit_zobrist(self):
return self.zobrist ^ Board.ZOBRIST_PLA[self.pla]
def num_liberties(self, loc):
if self.board[loc] == Board.EMPTY or self.board[loc] == Board.WALL:
return 0
return self.group_liberty_count[self.group_head[loc]]
def is_simple_eye(self, pla, loc):
adj0 = loc + self.adj[0]
adj1 = loc + self.adj[1]
adj2 = loc + self.adj[2]
adj3 = loc + self.adj[3]
if (self.board[adj0] != pla and self.board[adj0] != Board.WALL) or \
(self.board[adj1] != pla and self.board[adj1] != Board.WALL) or \
(self.board[adj2] != pla and self.board[adj2] != Board.WALL) or \
(self.board[adj3] != pla and self.board[adj3] != Board.WALL):
return False
opp = Board.get_opp(pla)
opp_corners = 0
diag0 = loc + self.diag[0]
diag1 = loc + self.diag[1]
diag2 = loc + self.diag[2]
diag3 = loc + self.diag[3]
if self.board[diag0] == opp:
opp_corners += 1
if self.board[diag1] == opp:
opp_corners += 1
if self.board[diag2] == opp:
opp_corners += 1
if self.board[diag3] == opp:
opp_corners += 1
if opp_corners >= 2:
return False
if opp_corners <= 0:
return True
against_wall = (
self.board[adj0] == Board.WALL or
self.board[adj1] == Board.WALL or
self.board[adj2] == Board.WALL or
self.board[adj3] == Board.WALL
)
if against_wall:
return False
return True
def would_be_legal(self, pla, loc):
if pla != Board.BLACK and pla != Board.WHITE:
return False
if loc == Board.PASS_LOC:
return True
if not self.is_on_board(loc):
return False
if self.board[loc] != Board.EMPTY:
return False
if self.would_be_single_stone_suicide(pla, loc):
return False
if loc == self.simple_ko_point:
return False
return True
def would_be_suicide(self, pla, loc):
adj0 = loc + self.adj[0]
adj1 = loc + self.adj[1]
adj2 = loc + self.adj[2]
adj3 = loc + self.adj[3]
opp = Board.get_opp(pla)
# If empty or capture, then not suicide
if self.board[adj0] == Board.EMPTY or (
self.board[adj0] == opp and self.group_liberty_count[self.group_head[adj0]] == 1) or \
self.board[adj1] == Board.EMPTY or (
self.board[adj1] == opp and self.group_liberty_count[self.group_head[adj1]] == 1) or \
self.board[adj2] == Board.EMPTY or (
self.board[adj2] == opp and self.group_liberty_count[self.group_head[adj2]] == 1) or \
self.board[adj3] == Board.EMPTY or (
self.board[adj3] == opp and self.group_liberty_count[self.group_head[adj3]] == 1):
return False
# If connects to own stone with enough liberties, then not suicide
if self.board[adj0] == pla and self.group_liberty_count[self.group_head[adj0]] > 1 or \
self.board[adj1] == pla and self.group_liberty_count[self.group_head[adj1]] > 1 or \
self.board[adj2] == pla and self.group_liberty_count[self.group_head[adj2]] > 1 or \
self.board[adj3] == pla and self.group_liberty_count[self.group_head[adj3]] > 1:
return False
return True
def would_be_single_stone_suicide(self, pla, loc):
adj0 = loc + self.adj[0]
adj1 = loc + self.adj[1]
adj2 = loc + self.adj[2]
adj3 = loc + self.adj[3]
opp = Board.get_opp(pla)
# If empty or capture, then not suicide
if self.board[adj0] == Board.EMPTY or (
self.board[adj0] == opp and self.group_liberty_count[self.group_head[adj0]] == 1) or \
self.board[adj1] == Board.EMPTY or (
self.board[adj1] == opp and self.group_liberty_count[self.group_head[adj1]] == 1) or \
self.board[adj2] == Board.EMPTY or (
self.board[adj2] == opp and self.group_liberty_count[self.group_head[adj2]] == 1) or \
self.board[adj3] == Board.EMPTY or (
self.board[adj3] == opp and self.group_liberty_count[self.group_head[adj3]] == 1):
return False
# If connects to own stone, then not single stone suicide
if self.board[adj0] == pla or \
self.board[adj1] == pla or \
self.board[adj2] == pla or \
self.board[adj3] == pla:
return False
return True
# Returns the number of liberties a new stone placed here would have, or maxLibs if it would be >= maxLibs.
def get_liberties_after_play(self, pla, loc, maxLibs):
opp = Board.get_opp(pla)
libs = []
capturedGroupHeads = []
# First, count immediate liberties and groups that would be captured
for i in range(4):
adj = loc + self.adj[i]
if self.board[adj] == Board.EMPTY:
libs.append(adj)
if len(libs) >= maxLibs:
return maxLibs
elif self.board[adj] == opp and self.num_liberties(adj) == 1:
libs.append(adj)
if len(libs) >= maxLibs:
return maxLibs
head = self.group_head[adj]
if head not in capturedGroupHeads:
capturedGroupHeads.append(head)
def wouldBeEmpty(possibleLib):
if self.board[possibleLib] == Board.EMPTY:
return True
elif self.board[possibleLib] == opp:
return (self.group_head[possibleLib] in capturedGroupHeads)
return False
# Next, walk through all stones of all surrounding groups we would connect with and count liberties, avoiding overlap.
connectingGroupHeads = []
for i in range(4):
adj = loc + self.adj[i]
if self.board[adj] == pla:
head = self.group_head[adj]
if head not in connectingGroupHeads:
connectingGroupHeads.append(head)
cur = adj
while True:
for k in range(4):
possibleLib = cur + self.adj[k]
if possibleLib != loc and wouldBeEmpty(possibleLib) and possibleLib not in libs:
libs.append(possibleLib)
if len(libs) >= maxLibs:
return maxLibs
cur = self.group_next[cur]
if cur == adj:
break
return len(libs)
def to_string(self):
def get_piece(x, y):
loc = self.loc(x, y)
if self.board[loc] == Board.BLACK:
return 'X '
elif self.board[loc] == Board.WHITE:
return 'O '
elif (x == 3 or x == self.size / 2 or x == self.size - 1 - 3) and (
y == 3 or y == self.size / 2 or y == self.size - 1 - 3):
return '* '
else:
return '. '
return "\n".join("".join(get_piece(x, y) for x in range(self.size)) for y in range(self.size))
def to_liberty_string(self):
def get_piece(x, y):
loc = self.loc(x, y)
if self.board[loc] == Board.BLACK or self.board[loc] == Board.WHITE:
libs = self.group_liberty_count[self.group_head[loc]]
if libs <= 9:
return str(libs) + ' '
else:
return '@ '
elif (x == 3 or x == self.size / 2 or x == self.size - 1 - 3) and (
y == 3 or y == self.size / 2 or y == self.size - 1 - 3):
return '* '
else:
return '. '
return "\n".join("".join(get_piece(x, y) for x in range(self.size)) for y in range(self.size))
def set_pla(self, pla):
self.pla = pla
def is_on_board(self, loc):
return loc >= 0 and loc < self.arrsize and self.board[loc] != Board.WALL
# Set a given location with error checking. Suicide setting allowed.
def set_stone(self, pla, loc):
if pla != Board.EMPTY and pla != Board.BLACK and pla != Board.WHITE:
raise IllegalMoveError("Invalid pla for board.set")
if not self.is_on_board(loc):
raise IllegalMoveError("Invalid loc for board.set")
if self.board[loc] == pla:
pass
elif self.board[loc] == Board.EMPTY:
self.add_unsafe(pla, loc)
elif pla == Board.EMPTY:
self.remove_single_stone_unsafe(loc)
else:
self.remove_single_stone_unsafe(loc)
self.add_unsafe(pla, loc)
# Clear any ko restrictions
self.simple_ko_point = None
# Play a stone at the given location, with non-superko legality checking and updating the pla and simple ko point
# Single stone suicide is disallowed but suicide is allowed, to support rule sets and sgfs that have suicide
def play(self, pla, loc):
if pla != Board.BLACK and pla != Board.WHITE:
raise IllegalMoveError("Invalid pla for board.play")
if loc != Board.PASS_LOC:
if not self.is_on_board(loc):
raise IllegalMoveError("Invalid loc for board.set")
if self.board[loc] != Board.EMPTY:
raise IllegalMoveError("Location is nonempty")
if self.would_be_single_stone_suicide(pla, loc):
raise IllegalMoveError("Move would be illegal single stone suicide")
if loc == self.simple_ko_point:
raise IllegalMoveError("Move would be illegal simple ko recapture")
self.playUnsafe(pla, loc)
def playUnsafe(self, pla, loc):
if loc == Board.PASS_LOC:
self.simple_ko_point = None
self.pla = Board.get_opp(pla)
else:
self.add_unsafe(pla, loc)
self.pla = Board.get_opp(pla)
def playRecordedUnsafe(self, pla, loc):
capDirs = []
opp = Board.get_opp(pla)
old_simple_ko_point = self.simple_ko_point
for i in range(4):
adj = loc + self.adj[i]
if self.board[adj] == opp and self.group_liberty_count[self.group_head[adj]] == 1:
capDirs.append(i)
self.playUnsafe(pla, loc)
# Suicide
selfCap = False
if self.board[loc] == Board.EMPTY:
selfCap = True
return (pla, loc, old_simple_ko_point, capDirs, selfCap)
def undo(self, record):
(pla, loc, simple_ko_point, capDirs, selfCap) = record
opp = Board.get_opp(pla)
self.simple_ko_point = simple_ko_point
self.pla = pla
if loc == Board.PASS_LOC:
return
# Re-fill stones in all captured directions
for capdir in capDirs:
adj = loc + self.adj[capdir]
if self.board[adj] == Board.EMPTY:
self.floodFillStones(opp, adj)
if selfCap:
self.floodFillStones(pla, loc)
# Delete the stone played here.
self.zobrist ^= Board.ZOBRIST_STONE[pla][loc]
self.board[loc] = Board.EMPTY
# Zero out stuff in preparation for rebuilding
head = self.group_head[loc]
stone_count = self.group_stone_count[head]
self.group_stone_count[head] = 0
self.group_liberty_count[head] = 0
# Uneat enemy liberties
self.changeSurroundingLiberties(loc, Board.get_opp(pla), +1)
# If this was not a single stone, we need to recompute the chain from scratch
if stone_count > 1:
# Run through the whole chain and make their heads point to nothing
cur = loc
while True:
self.group_head[cur] = Board.PASS_LOC
cur = self.group_next[cur]
if cur == loc:
break
# Rebuild each chain adjacent now
for i in range(4):
adj = loc + self.adj[i]
if self.board[adj] == pla and self.group_head[adj] == Board.PASS_LOC:
self.rebuildChain(pla, adj)
self.group_head[loc] = 0
self.group_next[loc] = 0
self.group_prev[loc] = 0
# Add a chain of the given player to the given region of empty space, floodfilling it.
# Assumes that this region does not border any chains of the desired color already
def floodFillStones(self, pla, loc):
head = loc
self.group_liberty_count[head] = 0
self.group_stone_count[head] = 0
# Add a chain with links front <-> ... <-> head <-> head with all head pointers towards head
front = self.floodFillStonesHelper(head, head, head, pla)
# Now, we make head point to front, and that completes the circle!
self.group_next[head] = front
self.group_prev[front] = head
# Floodfill a chain of the given color into this region of empty spaces
# Make the specified loc the head for all the chains and updates the chainData of head with the number of stones.
# Does NOT connect the stones into a circular list. Rather, it produces an linear linked list with the tail pointing
# to tailTarget, and returns the head of the list. The tail is guaranteed to be loc.
def floodFillStonesHelper(self, head, tailTarget, loc, pla):
self.board[loc] = pla
self.zobrist ^= Board.ZOBRIST_STONE[pla][loc]
self.group_head[loc] = head
self.group_stone_count[head] += 1
self.group_next[loc] = tailTarget
self.group_prev[tailTarget] = loc
# Eat enemy liberties
self.changeSurroundingLiberties(loc, Board.get_opp(pla), -1)
# Recursively add stones around us.
nextTailTarget = loc
for i in range(4):
adj = loc + self.adj[i]
if self.board[adj] == Board.EMPTY:
nextTailTarget = self.floodFillStonesHelper(head, nextTailTarget, adj, pla)
return nextTailTarget
# Floods through a chain of the specified player already on the board
# rebuilding its links and counting its liberties as we go.
# Requires that all their heads point towards
# some invalid location, such as PASS_LOC or a location not of color.
# The head of the chain will be loc.
def rebuildChain(self, pla, loc):
head = loc
self.group_liberty_count[head] = 0
self.group_stone_count[head] = 0
# Rebuild chain with links front <-> ... <-> head <-> head with all head pointers towards head
front = self.rebuildChainHelper(head, head, head, pla)
# Now, we make head point to front, and that completes the circle!
self.group_next[head] = front
self.group_prev[front] = head
# Does same thing as addChain, but floods through a chain of the specified color already on the board
# rebuilding its links and also counts its liberties as we go. Requires that all their heads point towards
# some invalid location, such as NULL_LOC or a location not of color.
def rebuildChainHelper(self, head, tailTarget, loc, pla):
# Count new liberties
for dloc in self.adj:
if self.board[loc + dloc] == Board.EMPTY and not self.is_group_adjacent(head, loc + dloc):
self.group_liberty_count[head] += 1
# Add stone here to the chain by setting its head
self.group_head[loc] = head
self.group_stone_count[head] += 1
self.group_next[loc] = tailTarget
self.group_prev[tailTarget] = loc
# Recursively add stones around us.
nextTailTarget = loc
for i in range(4):
adj = loc + self.adj[i]
if self.board[adj] == pla and self.group_head[adj] != head:
nextTailTarget = self.rebuildChainHelper(head, nextTailTarget, adj, pla)
return nextTailTarget
def add_unsafe(self, pla, loc):
""" Add a stone, assumes that the location is empty without checking
"""
opp = Board.get_opp(pla)
# Put the stone down
self.board[loc] = pla
self.zobrist ^= Board.ZOBRIST_STONE[pla][loc]
# Initialize the group for that stone
self.group_head[loc] = loc
self.group_stone_count[loc] = 1
liberties = 0
for dloc in self.adj:
if self.board[loc + dloc] == Board.EMPTY:
liberties += 1
self.group_liberty_count[loc] = liberties
self.group_next[loc] = loc
self.group_prev[loc] = loc
# Fill surrounding liberties of all adjacent groups
# Carefully avoid doublecounting
adj0 = loc + self.adj[0]
adj1 = loc + self.adj[1]
adj2 = loc + self.adj[2]
adj3 = loc + self.adj[3]
if self.board[adj0] == Board.BLACK or self.board[adj0] == Board.WHITE:
self.group_liberty_count[self.group_head[adj0]] -= 1
if self.board[adj1] == Board.BLACK or self.board[adj1] == Board.WHITE:
if self.group_head[adj1] != self.group_head[adj0]:
self.group_liberty_count[self.group_head[adj1]] -= 1
if self.board[adj2] == Board.BLACK or self.board[adj2] == Board.WHITE:
if self.group_head[adj2] != self.group_head[adj0] and \
self.group_head[adj2] != self.group_head[adj1]:
self.group_liberty_count[self.group_head[adj2]] -= 1
if self.board[adj3] == Board.BLACK or self.board[adj3] == Board.WHITE:
if self.group_head[adj3] != self.group_head[adj0] and \
self.group_head[adj3] != self.group_head[adj1] and \
self.group_head[adj3] != self.group_head[adj2]:
self.group_liberty_count[self.group_head[adj3]] -= 1
# Merge groups
if self.board[adj0] == pla:
self.merge_unsafe(loc, adj0)
if self.board[adj1] == pla:
self.merge_unsafe(loc, adj1)
if self.board[adj2] == pla:
self.merge_unsafe(loc, adj2)
if self.board[adj3] == pla:
self.merge_unsafe(loc, adj3)
# Resolve captures
opp_stones_captured = 0
caploc = 0
if self.board[adj0] == opp and self.group_liberty_count[self.group_head[adj0]] == 0:
opp_stones_captured += self.group_stone_count[self.group_head[adj0]]
caploc = adj0
self.remove_unsafe(adj0)
if self.board[adj1] == opp and self.group_liberty_count[self.group_head[adj1]] == 0:
opp_stones_captured += self.group_stone_count[self.group_head[adj1]]
caploc = adj1
self.remove_unsafe(adj1)
if self.board[adj2] == opp and self.group_liberty_count[self.group_head[adj2]] == 0:
opp_stones_captured += self.group_stone_count[self.group_head[adj2]]
caploc = adj2
self.remove_unsafe(adj2)
if self.board[adj3] == opp and self.group_liberty_count[self.group_head[adj3]] == 0:
opp_stones_captured += self.group_stone_count[self.group_head[adj3]]
caploc = adj3
self.remove_unsafe(adj3)
# Suicide
if self.group_liberty_count[self.group_head[loc]] == 0:
self.remove_unsafe(loc)
# Update ko point for legality checking
if opp_stones_captured == 1 and \
self.group_stone_count[self.group_head[loc]] == 1 and \
self.group_liberty_count[self.group_head[loc]] == 1:
self.simple_ko_point = caploc
else:
self.simple_ko_point = None
# Apply the specified delta to the liberties of all adjacent groups of the specified color
def changeSurroundingLiberties(self, loc, pla, delta):
# Carefully avoid doublecounting
adj0 = loc + self.adj[0]
adj1 = loc + self.adj[1]
adj2 = loc + self.adj[2]
adj3 = loc + self.adj[3]
if self.board[adj0] == pla:
self.group_liberty_count[self.group_head[adj0]] += delta
if self.board[adj1] == pla:
if self.group_head[adj1] != self.group_head[adj0]:
self.group_liberty_count[self.group_head[adj1]] += delta
if self.board[adj2] == pla:
if self.group_head[adj2] != self.group_head[adj0] and \
self.group_head[adj2] != self.group_head[adj1]:
self.group_liberty_count[self.group_head[adj2]] += delta
if self.board[adj3] == pla:
if self.group_head[adj3] != self.group_head[adj0] and \
self.group_head[adj3] != self.group_head[adj1] and \
self.group_head[adj3] != self.group_head[adj2]:
self.group_liberty_count[self.group_head[adj3]] += delta
def countImmediateLiberties(self, loc):
adj0 = loc + self.adj[0]
adj1 = loc + self.adj[1]
adj2 = loc + self.adj[2]
adj3 = loc + self.adj[3]
count = 0
if self.board[adj0] == Board.EMPTY:
count += 1
if self.board[adj1] == Board.EMPTY:
count += 1
if self.board[adj2] == Board.EMPTY:
count += 1
if self.board[adj3] == Board.EMPTY:
count += 1
return count
def is_group_adjacent(self, head, loc):
return (
self.group_head[loc + self.adj[0]] == head or \
self.group_head[loc + self.adj[1]] == head or \
self.group_head[loc + self.adj[2]] == head or \
self.group_head[loc + self.adj[3]] == head
)
# Helper, merge two groups assuming they're owned by the same player and adjacent
def merge_unsafe(self, loc0, loc1):
if self.group_stone_count[self.group_head[loc0]] >= self.group_stone_count[self.group_head[loc1]]:
parent = loc0
child = loc1
else:
child = loc0
parent = loc1
phead = self.group_head[parent]
chead = self.group_head[child]
if phead == chead:
return
# Walk the child group assigning the new head and simultaneously counting liberties
new_stone_count = self.group_stone_count[phead] + self.group_stone_count[chead]
new_liberties = self.group_liberty_count[phead]
loc = child
while True:
adj0 = loc + self.adj[0]
adj1 = loc + self.adj[1]
adj2 = loc + self.adj[2]
adj3 = loc + self.adj[3]
# Any adjacent empty space is a new liberty as long as it isn't adjacent to the parent
if self.board[adj0] == Board.EMPTY and not self.is_group_adjacent(phead, adj0):
new_liberties += 1
if self.board[adj1] == Board.EMPTY and not self.is_group_adjacent(phead, adj1):
new_liberties += 1
if self.board[adj2] == Board.EMPTY and not self.is_group_adjacent(phead, adj2):
new_liberties += 1
if self.board[adj3] == Board.EMPTY and not self.is_group_adjacent(phead, adj3):
new_liberties += 1
# Now assign the new parent head to take over the child (this also
# prevents double-counting liberties)
self.group_head[loc] = phead
# Advance around the linked list
loc = self.group_next[loc]
if loc == child:
break
# Zero out the old head
self.group_stone_count[chead] = 0
self.group_liberty_count[chead] = 0
# Update the new head
self.group_stone_count[phead] = new_stone_count
self.group_liberty_count[phead] = new_liberties
# Combine the linked lists
plast = self.group_prev[phead]
clast = self.group_prev[chead]
self.group_next[clast] = phead
self.group_next[plast] = chead
self.group_prev[chead] = plast
self.group_prev[phead] = clast
# Remove all stones in a group
def remove_unsafe(self, group):
head = self.group_head[group]
pla = self.board[group]
opp = Board.get_opp(pla)
# Walk all the stones in the group and delete them
loc = group
while True:
# Add a liberty to all surrounding opposing groups, taking care to avoid double counting
adj0 = loc + self.adj[0]
adj1 = loc + self.adj[1]
adj2 = loc + self.adj[2]
adj3 = loc + self.adj[3]
if self.board[adj0] == opp:
self.group_liberty_count[self.group_head[adj0]] += 1
if self.board[adj1] == opp:
if self.group_head[adj1] != self.group_head[adj0]:
self.group_liberty_count[self.group_head[adj1]] += 1
if self.board[adj2] == opp:
if self.group_head[adj2] != self.group_head[adj0] and \
self.group_head[adj2] != self.group_head[adj1]:
self.group_liberty_count[self.group_head[adj2]] += 1
if self.board[adj3] == opp:
if self.group_head[adj3] != self.group_head[adj0] and \
self.group_head[adj3] != self.group_head[adj1] and \
self.group_head[adj3] != self.group_head[adj2]:
self.group_liberty_count[self.group_head[adj3]] += 1
next_loc = self.group_next[loc]
# Zero out all the stuff
self.board[loc] = Board.EMPTY
self.zobrist ^= Board.ZOBRIST_STONE[opp][loc]
self.group_head[loc] = 0
self.group_next[loc] = 0
self.group_prev[loc] = 0
# Advance around the linked list
loc = next_loc
if loc == group:
break
# Zero out the head
self.group_stone_count[head] = 0
self.group_liberty_count[head] = 0
# Remove a single stone
def remove_single_stone_unsafe(self, rloc):
pla = self.board[rloc]
# Record all the stones in the group
stones = []
loc = rloc
while True:
stones.append(loc)
loc = self.group_next[loc]
if loc == rloc:
break
# Remove them all
self.remove_unsafe(rloc)
# Then add them back one by one
for loc in stones:
if loc != rloc:
self.add_unsafe(pla, loc)
# Helper, find liberties of group at loc. Fills in buf.
def findLiberties(self, loc, buf):
cur = loc
while True:
for i in range(4):
lib = cur + self.adj[i]
if self.board[lib] == Board.EMPTY:
if lib not in buf:
buf.append(lib)
cur = self.group_next[cur]
if cur == loc:
break
# Helper, find captures that gain liberties for the group at loc. Fills in buf
def findLibertyGainingCaptures(self, loc, buf):
pla = self.board[loc]
opp = Board.get_opp(pla)
# For performance, avoid checking for captures on any chain twice
chainHeadsChecked = []
cur = loc
while True:
for i in range(4):
adj = cur + self.adj[i]
if self.board[adj] == opp:
head = self.group_head[adj]
if self.group_liberty_count[head] == 1:
if head not in chainHeadsChecked:
# Capturing moves are precisely the liberties of the groups around us with 1 liberty.
self.findLiberties(adj, buf)
chainHeadsChecked.append(head)
cur = self.group_next[cur]
if cur == loc:
break
# Helper, does the group at loc have at least one opponent group adjacent to it in atari?
def hasLibertyGainingCaptures(self, loc):
pla = self.board[loc]
opp = Board.get_opp(pla)
cur = loc
while True:
for i in range(4):
adj = cur + self.adj[i]
if self.board[adj] == opp:
head = self.group_head[adj]
if self.group_liberty_count[head] == 1:
return True
cur = self.group_next[cur]
if cur == loc:
break
return False
def wouldBeKoCapture(self, loc, pla):
if self.board[loc] == Board.EMPTY:
return False
# Check that surounding points are are all opponent owned and exactly one of them is capturable
opp = Board.get_opp(pla)
oppCapturableLoc = None
for i in range(4):
adj = loc + self.adj[i]
if self.board[adj] != Board.WALL and self.board[adj] != opp:
return False
if self.board[adj] == opp and self.group_liberty_count[self.group_head[adj]] == 1:
if oppCapturableLoc is not None:
return False
oppCapturableLoc = adj
if oppCapturableLoc is None:
return False
# Check that the capturable loc has exactly one stone
if self.group_stone_count[self.group_head[oppCapturableLoc]] != 1:
return False
return True
def countHeuristicConnectionLiberties(self, loc, pla):
adj0 = loc + self.adj[0]
adj1 = loc + self.adj[1]
adj2 = loc + self.adj[2]
adj3 = loc + self.adj[3]
count = 0.0
if self.board[adj0] == pla:
count += max(0.0, self.group_liberty_count[self.group_head[adj0]] - 1.5)
if self.board[adj1] == pla:
count += max(0.0, self.group_liberty_count[self.group_head[adj1]] - 1.5)
if self.board[adj2] == pla:
count += max(0.0, self.group_liberty_count[self.group_head[adj2]] - 1.5)
if self.board[adj3] == pla:
count += max(0.0, self.group_liberty_count[self.group_head[adj3]] - 1.5)
return count
def searchIsLadderCapturedAttackerFirst2Libs(self, loc):
if not self.is_on_board(loc):
return []
if self.board[loc] != Board.BLACK and self.board[loc] != Board.WHITE:
return []
if self.group_liberty_count[self.group_head[loc]] != 2:
return []
# Make it so that pla is always the defender
pla = self.board[loc]
opp = Board.get_opp(pla)
moves = []
self.findLiberties(loc, moves)
assert (len(moves) == 2)
move0 = moves[0]
move1 = moves[1]
move0Works = False
move1Works = False
if self.would_be_legal(opp, move0):
record = self.playRecordedUnsafe(opp, move0)
move0Works = self.searchIsLadderCaptured(loc, True)
self.undo(record)
if self.would_be_legal(opp, move1):
record = self.playRecordedUnsafe(opp, move1)
move1Works = self.searchIsLadderCaptured(loc, True)
self.undo(record)
workingMoves = []
if move0Works:
workingMoves.append(move0)
if move1Works:
workingMoves.append(move1)
return workingMoves
def searchIsLadderCaptured(self, loc, defenderFirst):
if not self.is_on_board(loc):
return False
if self.board[loc] != Board.BLACK and self.board[loc] != Board.WHITE:
return False
if self.group_liberty_count[self.group_head[loc]] > 2 or (
defenderFirst and self.group_liberty_count[self.group_head[loc]] > 1):
return False
# Make it so that pla is always the defender
pla = self.board[loc]
opp = Board.get_opp(pla)
arrSize = self.size * self.size * 2 # A bit bigger due to paranoia about recaptures making the sequence longer.
# Stack for the search. These are lists of possible moves to search at each level of the stack
moveLists = [[] for i in range(arrSize)]
moveListCur = [0 for i in
range(arrSize)] # Current move list idx searched, equal to -1 if list has not been generated.
records = [None for i in range(arrSize)] # Records so that we can undo moves as we search back up.
stackIdx = 0
moveLists[0] = []
moveListCur[0] = -1
returnValue = False
returnedFromDeeper = False
# Clear the ko loc for the defender at the root node - assume all kos work for the defender
saved_simple_ko_point = self.simple_ko_point
if defenderFirst:
self.simple_ko_point = None
# debug = True
# if debug:
# print("SEARCHING " + str(self.loc_x(loc)) + " " + str(self.loc_y(loc)))
while True:
# if debug:
# print(str(stackIdx) + " " + str(moveListCur[stackIdx]) + "/" + str(len(moveLists[stackIdx])) + " " + str(returnValue) + " " + str(returnedFromDeeper))
# Returned from the root - so that's the answer
if stackIdx <= -1:
assert (stackIdx == -1)
self.simple_ko_point = saved_simple_ko_point
return returnValue
isDefender = (defenderFirst and (stackIdx % 2) == 0) or (not defenderFirst and (stackIdx % 2) == 1)
# We just entered this level?
if moveListCur[stackIdx] == -1:
libs = self.group_liberty_count[self.group_head[loc]]
# Base cases.
# If we are the attacker and the group has only 1 liberty, we already win.
if not isDefender and libs <= 1:
returnValue = True
returnedFromDeeper = True
stackIdx -= 1
continue
# If we are the attacker and the group has 3 liberties, we already lose.
if not isDefender and libs >= 3:
returnValue = False
returnedFromDeeper = True
stackIdx -= 1
continue
# If we are the defender and the group has 2 liberties, we already win.
if isDefender and libs >= 2:
returnValue = False
returnedFromDeeper = True
stackIdx -= 1
continue
# If we are the defender and the attacker left a simple ko point, assume we already win
# because we don't want to say yes on ladders that depend on kos
# This should also hopefully prevent any possible infinite loops - I don't know of any infinite loop
# that would come up in a continuous atari sequence that doesn't ever leave a simple ko point.
if isDefender and self.simple_ko_point is not None:
returnValue = False
returnedFromDeeper = True
stackIdx -= 1
continue
# Otherwise we need to keep searching.
# Generate the move list. Attacker and defender generate moves on the group's liberties, but only the defender
# generates moves on surrounding capturable opposing groups.
if isDefender:
moveLists[stackIdx] = []
self.findLibertyGainingCaptures(loc, moveLists[stackIdx])
self.findLiberties(loc, moveLists[stackIdx])
else:
moveLists[stackIdx] = []
self.findLiberties(loc, moveLists[stackIdx])
assert (len(moveLists[stackIdx]) == 2)
# Early quitouts if the liberties are not adjacent
# (so that filling one doesn't fill an immediate liberty of the other)
move0 = moveLists[stackIdx][0]
move1 = moveLists[stackIdx][1]
libs0 = self.countImmediateLiberties(move0)
libs1 = self.countImmediateLiberties(move1)
# If we are the attacker and we're in a double-ko death situation, then assume we win.