daniel156161
3a9af3f54d
- Split active strategies, reusable engine code, core classes, and legacy snakes. - Replace implicit snake imports with explicit module registrations. - Extract Prism duel, spatial, and survival behavior into focused mixins. - Improve duel scoring with food races, pressure, caches, and depth metrics. - Add deterministic arena scenarios and paired seeded engine tournaments. - Expand benchmark telemetry and bump Prism to version 1.3.0. - Update documentation and tests for the new package layout and tooling.
215 lines
8.1 KiB
Python
215 lines
8.1 KiB
Python
"""Reusable bitboard and adversarial survival rollouts."""
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from __future__ import annotations
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from time import perf_counter
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from snakes.engine.survival_search import CompactSurvivalSearch
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class BitboardSurvivalMixin:
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def _future_rollout_bonus(
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self, move: str, safe_moves: dict, my_body: list, other_snakes: list,
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food_set: set, is_constrictor: bool, width: int, height: int,
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enemy_can_grow: dict, deadline: float | None,
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) -> float:
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pos = safe_moves.get(move)
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if pos is None:
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return -250.0
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# Duel minimax already advances the opponent exactly. Keep the much faster
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# bitboard-native solo rollout here instead of paying for the same response
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# model twice. Constrictor and multiplayer still use adversarial rollouts.
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if len(other_snakes) == 1 and not is_constrictor:
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return super()._future_rollout_bonus(
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move, safe_moves, my_body, other_snakes, food_set, is_constrictor,
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width, height, enemy_can_grow, deadline,
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)
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if self._survival_search_context is None:
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remaining = self._remaining_ms(deadline)
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enemy_branch = 2 if len(other_snakes) <= 2 and remaining > 100 else 1
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self._survival_search_context = CompactSurvivalSearch(
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board=self._get_bb(width, height),
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food=food_set,
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is_constrictor=is_constrictor,
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deadline=deadline,
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branch=self._planning_branch,
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enemy_branch=enemy_branch,
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response_cap=8 if remaining > 150 else 4,
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)
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remaining = self._remaining_ms(deadline)
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depth = min(self._planning_depth, 2 if len(other_snakes) > 1 else 3)
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if remaining < 90:
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depth = min(depth, 2)
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elif remaining > 250 and len(other_snakes) <= 2:
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depth = min(4, depth + 1)
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raw = self._survival_search_context.search_selected(
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my_body=my_body,
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enemies=other_snakes,
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target=(pos["x"], pos["y"]),
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depth=depth,
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)
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return raw * 0.15
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def _future_position_score(
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self, my_body: list, other_snakes: list, food_set: set, is_constrictor: bool,
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width: int, height: int, enemy_can_grow: dict, deadline: float | None,
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) -> float:
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"""S9: Bitboard-native position scoring for the survival tree.
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Builds blocked bitboard directly from body lists (no intermediate set).
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Uses precomputed enemy bits instead of rebuilding attack map per node.
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"""
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if deadline is not None and perf_counter() >= deadline:
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return 0.0
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bb = self._bb # already initialised in choose_move
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w = bb.width
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head = my_body[0]
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hx, hy = head["x"], head["y"]
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head_idx = hy * w + hx
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head_bit = 1 << head_idx
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body_len = len(my_body)
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# ── Build blocked bitboard directly (no set) ──────────────────────
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my_bits = 0
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for seg in my_body:
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my_bits |= 1 << (seg["y"] * w + seg["x"])
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# Own tail vacates unless stacked or constrictor
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if not is_constrictor and body_len >= 2:
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t, t2 = my_body[-1], my_body[-2]
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if not (t["x"] == t2["x"] and t["y"] == t2["y"]):
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my_bits &= ~(1 << (t["y"] * w + t["x"]))
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# Enemy body (precomputed) minus vacating tails
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en_bits = self._enemy_body_bits & ~self._enemy_tail_bits
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blocked_bits = (my_bits | en_bits) & ~head_bit
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# ── Reachable space ───────────────────────────────────────────────
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reachable = bb.flood_count(head_idx, blocked_bits)
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required = body_len + max(3, body_len // 6) if is_constrictor else body_len
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if reachable < required:
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return -5000.0
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# ── Open neighbours (liberties) ───────────────────────────────────
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nb_free = bb._neighbor_masks[head_idx] & ~blocked_bits & bb.board_mask
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liberties = nb_free.bit_count()
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if liberties == 0:
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return -5000.0
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# ── Safe next options (enemy-attack aware) ────────────────────────
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# Rebuild danger for the simulated length. The root-turn danger mask is
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# stale after eating and includes enemy moves blocked in this future body.
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danger_here = 0
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for enemy in other_snakes:
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enemy_len = enemy.get("length", len(enemy["body"]))
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if enemy_len < body_len:
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continue
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enemy_head = enemy["head"]
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enemy_idx = enemy_head["y"] * w + enemy_head["x"]
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danger_here |= bb._neighbor_masks[enemy_idx]
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danger_here &= ~blocked_bits
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safe_nb = nb_free & ~danger_here
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en_safe = safe_nb.bit_count()
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if en_safe == 0:
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return -4000.0
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next_opts = liberties
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sc = reachable * 1.9 + liberties * 14.0 + next_opts * 11.0 + en_safe * 26.0
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if en_safe == 1:
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sc -= 420.0
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return sc
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def _future_survival_tree(
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self, my_body: list, other_snakes: list, food_set: set, is_constrictor: bool,
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width: int, height: int, enemy_can_grow: dict,
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depth: int, branch: int, deadline: float | None,
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) -> float:
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"""S9/S11: Bitboard-accelerated survival tree.
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Inlines legal-move check with bitboard ops instead of per-direction
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Python loops. Uses the bitboard-native _future_position_score.
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"""
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if depth <= 0 or (deadline is not None and perf_counter() >= deadline):
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return 0.0
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bb = self._bb
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w = bb.width
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head = my_body[0]
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hx, hy = head["x"], head["y"]
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head_idx = hy * w + hx
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body_len = len(my_body)
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# ── Build occupied bitboard for legal-move check ──────────────────
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occupied_bits = 0
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for seg in my_body:
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occupied_bits |= 1 << (seg["y"] * w + seg["x"])
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occupied_bits |= self._enemy_body_bits
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# Own tail can be stepped on if not stacked/constrictor
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passable = 0
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if not is_constrictor and body_len >= 2:
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t, t2 = my_body[-1], my_body[-2]
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if not (t["x"] == t2["x"] and t["y"] == t2["y"]):
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passable |= 1 << (t["y"] * w + t["x"])
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# Enemy vacating tails are also steppable
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passable |= self._enemy_tail_bits
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# Legal moves: free neighbours OR passable tiles
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legal_bits = bb._neighbor_masks[head_idx] & ((~occupied_bits & bb.board_mask) | passable)
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if not legal_bits:
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return -5000.0
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# ── Precompute food bitboard once ─────────────────────────────────
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food_bits_local = 0
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for fx, fy in food_set:
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food_bits_local |= 1 << (fy * w + fx)
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# ── Score each legal move ─────────────────────────────────────────
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scored: list[tuple[float, list]] = []
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temp = legal_bits
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while temp:
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if deadline is not None and perf_counter() >= deadline:
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break
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bit = temp & (-temp)
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temp ^= bit
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idx = bit.bit_length() - 1
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nx, ny = idx % w, idx // w
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pos = {"x": nx, "y": ny}
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ate = bool(bit & food_bits_local)
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fb = self._future_body(my_body, pos, ate, is_constrictor)
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sc = self._future_position_score(
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fb, other_snakes, food_set, is_constrictor,
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width, height, enemy_can_grow, deadline,
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)
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scored.append((sc, fb))
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if not scored:
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return -5000.0
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DEATH = self._TREE_DEATH_THRESHOLD
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viable = [(sc, fb) for sc, fb in scored if sc > DEATH]
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if not viable:
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return max(sc for sc, _ in scored)
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viable.sort(key=lambda x: x[0], reverse=True)
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if depth == 1:
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return viable[0][0]
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best = viable[0][0]
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for sc, fb in viable[:branch]:
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if deadline is not None and perf_counter() >= deadline:
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break
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cont = self._future_survival_tree(
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fb, other_snakes, food_set, is_constrictor,
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width, height, enemy_can_grow, depth - 1, branch, deadline,
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)
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total = sc + cont * 0.72
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if total > best:
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best = total
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return best
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