Files
katrain-qt/katrain/core/ai.py
T
2020-06-01 14:01:15 +02:00

219 lines
11 KiB
Python

import heapq
import math
import random
import time
from typing import Dict, List, Tuple
from katrain.core.utils import var_to_grid
from katrain.core.constants import (
OUTPUT_INFO,
OUTPUT_DEBUG,
AI_STRATEGIES_POLICY,
AI_POLICY,
AI_WEIGHTED,
AI_STRATEGIES_PICK,
AI_JIGO,
AI_SCORELOSS,
AI_DEFAULT,
AI_INFLUENCE,
AI_LOCAL,
AI_TENUKI,
AI_TERRITORY, AI_PICK,
)
from katrain.core.engine import EngineDiedException
from katrain.core.game import Game, GameNode, Move
def weighted_selection_without_replacement(items: List[Tuple], pick_n: int) -> List[Tuple]:
"""For a list of tuples where the second element is a weight, returns random items with those weights, without replacement."""
elt = [(math.log(random.random()) / item[1], item) for item in items] # magic
return [e[1] for e in heapq.nlargest(pick_n, elt)] # NB fine if too small
def dirichlet_noise(num, dir_alpha=0.3):
sample = [random.gammavariate(dir_alpha, 1) for _ in range(num)]
sum_sample = sum(sample)
return [s / sum_sample for s in sample]
def fmt_moves(moves: List[Tuple[float, Move]]):
return ", ".join(f"{mv.gtp()} ({p:.2%})" for p, mv in moves)
def ai_move(game: Game, ai_mode: str, ai_settings: Dict) -> Tuple[Move, GameNode]:
cn = game.current_node
while not cn.analysis_ready:
time.sleep(0.01)
engine = game.engines[cn.next_player]
if engine.katago_process.poll() is not None: # TODO: clean up
raise EngineDiedException(f"Engine for {cn.next_player} ({engine.config}) died")
ai_thoughts = ""
if (ai_mode in AI_STRATEGIES_POLICY) and cn.policy: # pure policy based move
policy_moves = cn.policy_ranking
pass_policy = cn.policy[-1]
top_5_pass = any(
[polmove[1].is_pass for polmove in policy_moves[:5]]
) # dont make it jump around for the last few sensible non pass moves
size = game.board_size
policy_grid = var_to_grid(cn.policy, size) # type: List[List[float]]
top_policy_move = policy_moves[0][1]
ai_thoughts += f"Using policy based strategy, base top 5 moves are {fmt_moves(policy_moves[:5])}. "
if ai_mode == AI_POLICY and cn.depth <= ai_settings["opening_moves"]:
ai_mode = AI_WEIGHTED
ai_thoughts += f"Switching to weighted strategy in the opening {int(ai_settings['opening_moves'])} moves. "
ai_settings = {"pick_override": 0.9, "weaken_fac": 1, "lower_bound": 0.02}
if top_5_pass:
aimove = top_policy_move
ai_thoughts += "Playing top one because one of them is pass."
elif ai_mode == AI_POLICY:
aimove = top_policy_move
ai_thoughts += f"Playing top policy move {aimove.gtp()}."
elif policy_moves[0][0] > ai_settings["pick_override"]:
aimove = top_policy_move
ai_thoughts += (
f"Top policy move has weight > {ai_settings['pick_override']:.1%}, so overriding other strategies."
)
elif ai_mode == AI_WEIGHTED:
lower_bound = max(0, ai_settings["lower_bound"]) * 2 # compensate for first halving in loop
weaken_fac = max(0.01, ai_settings["weaken_fac"])
weighted_coords = []
while not weighted_coords and lower_bound > 1e-6: # fix edge case where no moves are > lb
lower_bound /= 2
weighted_coords = [
(policy_grid[y][x], policy_grid[y][x] ** (1 / weaken_fac), x, y)
for x in range(size[0])
for y in range(size[1])
if policy_grid[y][x] > lower_bound
]
top = weighted_selection_without_replacement(weighted_coords, 1)
if top:
best = top[0]
policy_value = best[0]
coords = best[2:]
else:
policy_value = pass_policy
coords = None
aimove = Move(coords, player=cn.next_player) # just take a random move by policy w/o noise
ai_thoughts += f"Playing policy-weighted random move {aimove.gtp()} ({policy_value:.1%})" + (
" because no other moves were found."
if not top
else f" because strategy is weighted (lower bound={lower_bound:.2%}, num moves > lb={len(weighted_coords)})."
)
elif ai_mode in AI_STRATEGIES_PICK:
legal_policy_moves = [(pol, mv) for pol, mv in policy_moves if not mv.is_pass if pol > 0]
n_moves = int(ai_settings["pick_frac"] * len(legal_policy_moves) + ai_settings["pick_n"])
if ai_mode in [AI_INFLUENCE, AI_TERRITORY]:
thr_line = ai_settings["threshold"] - 1 # zero-based
if cn.depth >= ai_settings["endgame"] * size[0] * size[1]:
weighted_coords = [
(policy_grid[y][x], 1, x, y)
for x in range(size[0])
for y in range(size[1])
if policy_grid[y][x] > 0
]
ai_thoughts += (
f"Generated equal weights as move number >= {ai_settings['endgame'] * size[0] * size[1]}. "
)
else:
if ai_mode == AI_INFLUENCE:
weight = lambda x, y: (1 / ai_settings["line_weight"]) ** (
max(0, thr_line - min(size[0] - 1 - x, x)) + max(0, thr_line - min(size[1] - 1 - y, y))
)
else:
weight = lambda x, y: (1 / ai_settings["line_weight"]) ** (
max(0, min(size[0] - 1 - x, x, size[1] - 1 - y, y) - thr_line)
)
weighted_coords = [
(policy_grid[y][x] * weight(x, y), weight(x, y), x, y)
for x in range(size[0])
for y in range(size[1])
if policy_grid[y][x] > 0
]
ai_thoughts += f"Generated weights for {ai_mode} according to weight factor {ai_settings['line_weight']} and distance from {thr_line+1}th line. "
elif ai_mode in [AI_LOCAL, AI_TENUKI]:
var = ai_settings["stddev"] ** 2
if not cn.move or cn.move.coords is None:
weighted_coords = [(1, 1, *top_policy_move.coords)] # if "pick" in ai_mode -> even
ai_thoughts += f"No previous non-pass move, faking weights to play top policy move. "
else:
mx, my = cn.move.coords
weighted_coords = [
(policy_grid[y][x], math.exp(-0.5 * ((x - mx) ** 2 + (y - my) ** 2) / var), x, y)
for x in range(size[0])
for y in range(size[1])
if policy_grid[y][x] > 0
]
if ai_mode == AI_TENUKI:
if cn.depth < ai_settings["endgame"] * size[0] * size[1]:
weighted_coords = [(p, 1 - w, x, y) for p, w, x, y in weighted_coords]
ai_thoughts += f"Generated weights based on one minus gaussian with variance {var} around coordinates {mx},{my}. "
else:
weighted_coords = [(p, 1, x, y) for p, w, x, y in weighted_coords]
ai_thoughts += f"Generated equal weights as move number >= {ai_settings['endgame'] * size[0] * size[1]}. "
else:
ai_thoughts += (
f"Generated weights based on gaussian with variance {var} around coordinates {mx},{my}. "
)
elif ai_mode == AI_PICK:
weighted_coords = [
(policy_grid[y][x], 1, x, y)
for x in range(size[0])
for y in range(size[1])
if policy_grid[y][x] > 0
]
else:
raise ValueError(f"Unknown AI mode {ai_mode}")
pick_moves = weighted_selection_without_replacement(weighted_coords, n_moves)
ai_thoughts += f"Picked {min(n_moves,len(weighted_coords))} random moves according to weights. "
if pick_moves:
new_top = [(p, Move((x, y), player=cn.next_player)) for p, wt, x, y in heapq.nlargest(5, pick_moves)]
aimove = new_top[0][1]
ai_thoughts += f"Top 5 among these were {fmt_moves(new_top)} and picked top {aimove.gtp()}. "
if new_top[0][0] < pass_policy:
ai_thoughts += f"But found pass ({pass_policy:.2%} to be higher rated than {aimove.gtp()} ({new_top[0][0]:.2%}) so will play top policy move instead."
aimove = top_policy_move
else:
aimove = top_policy_move
ai_thoughts += f"Pick policy strategy {ai_mode} failed to find legal moves, so is playing top policy move {aimove.gtp()}."
else:
raise ValueError(f"Unknown AI mode {ai_mode}")
else: # Engine based move
candidate_ai_moves = cn.candidate_moves
top_cand = Move.from_gtp(candidate_ai_moves[0]["move"], player=cn.next_player)
if top_cand.is_pass: # don't play suicidal to balance score - pass when it's best
aimove = top_cand
ai_thoughts += f"Top move is pass, so passing regardless of strategy."
else:
if ai_mode == AI_JIGO:
sign = cn.player_sign(cn.next_player)
jigo_move = min(
candidate_ai_moves, key=lambda move: abs(sign * move["scoreLead"] - ai_settings["target_score"])
)
aimove = Move.from_gtp(jigo_move["move"], player=cn.next_player)
ai_thoughts += f"Jigo strategy found {len(candidate_ai_moves)} candidate moves (best {top_cand.gtp()}) and chose {aimove.gtp()} as closest to 0.5 point win"
elif ai_mode == AI_SCORELOSS:
c = ai_settings["strength"]
moves = [
(
d["pointsLost"],
math.exp(min(200, -c * max(0, d["pointsLost"]))),
Move.from_gtp(d["move"], player=cn.next_player),
)
for d in candidate_ai_moves
]
topmove = weighted_selection_without_replacement(moves, 1)[0]
aimove = topmove[2]
ai_thoughts += f"ScoreLoss strategy found {len(candidate_ai_moves)} candidate moves (best {top_cand.gtp()}) and chose {aimove.gtp()} (weight {topmove[1]:.3f}, point loss {topmove[0]:.1f}) based on score weights."
else:
if ai_mode != AI_DEFAULT:
game.katrain.log(f"Unknown AI mode {ai_mode} or policy missing, using default.", OUTPUT_INFO)
ai_thoughts += f"Strategy {ai_mode} not found or unexpected fallback."
aimove = top_cand
ai_thoughts += f"Default strategy found {len(candidate_ai_moves)} moves returned from the engine and chose {aimove.gtp()} as top move"
game.katrain.log(f"AI thoughts: {ai_thoughts}", OUTPUT_DEBUG)
played_node = game.play(aimove)
played_node.ai_thoughts = ai_thoughts
return aimove, played_node