{ "config": "B + S + L (stack-b with silence-a re-implementation and slow-path PHAT_ALPHA_RETAIL 0.03; no N mix). No tuning.", "code": "// SPDX-License-Identifier: MIT\npragma solidity ^0.8.24;\n\nimport {AMMStrategyBase} from \"./AMMStrategyBase.sol\";\nimport {TradeInfo} from \"./IAMMStrategy.sol\";\n\ncontract Strategy is AMMStrategyBase {\n uint256 constant ELAPSED_CAP = 8;\n uint256 constant SIGNAL_THRESHOLD = WAD / 650;\n uint256 constant DIR_DECAY = 750000000000000000;\n uint256 constant ACT_DECAY = 530000000000000000;\n uint256 constant SIZE_DECAY = 530000000000000000;\n uint256 constant TOX_DECAY = 910000000000000000;\n uint256 constant SIGMA_DECAY = 690000000000000000;\n uint256 constant LAMBDA_DECAY = 990000000000000000;\n uint256 constant SIZE_BLEND_DECAY = 828000000000000000;\n uint256 constant TOX_BLEND_DECAY = 51000000000000000;\n uint256 constant ACT_BLEND_DECAY = 985000000000000000;\n uint256 constant PHAT_ALPHA = 270000000000000000;\n uint256 constant PHAT_ALPHA_RETAIL = 60000000000000000;\n uint256 constant PHAT_ALPHA_SAME = 120000000000000000;\n uint256 constant REVERT_U = 0;\n uint256 constant DIR_IMPACT_MULT = 4;\n uint256 constant GATE_SIGMA_MULT = 7200000000000000000;\n uint256 constant MIN_GATE = 30000000000000000;\n uint256 constant TRADE_TOX_BOOST = 3500 * BPS;\n uint256 constant STALE_ATTRACT_FRAC = 1050000000000000000;\n uint256 constant RET_CAP = WAD / 35;\n uint256 constant TOX_CAP = WAD / 5;\n uint256 constant TRADE_RATIO_CAP = WAD / 5;\n uint256 constant LAMBDA_CAP = 1820000000000000000;\n uint256 constant STEP_COUNT_CAP = 64;\n uint256 constant BASE_FEE = 4 * BPS;\n uint256 constant SIGMA_COEF = 200000000000000000;\n uint256 constant LAMBDA_COEF = 12 * BPS;\n uint256 constant FLOW_SIZE_COEF = 4842 * BPS;\n uint256 constant TOX_COEF = 300 * BPS;\n uint256 constant TOX_QUAD_COEF = 15000 * BPS;\n uint256 constant ACT_COEF = 91843 * BPS;\n uint256 constant DIR_COEF = 20 * BPS;\n uint256 constant DIR_TOX_COEF = 100 * BPS;\n uint256 constant STALE_DIR_COEF = 6850 * BPS;\n uint256 constant SIGMA_TOX_COEF = 500 * BPS;\n uint256 constant TAIL_KNEE = 600 * BPS;\n uint256 constant TAIL_SLOPE_PROTECT = 930000000000000000;\n uint256 constant TAIL_SLOPE_ATTRACT = 850000000000000000;\n\n function afterInitialize(uint256 initialX, uint256 initialY) external override returns (uint256, uint256) {\n slots[0] = BASE_FEE; slots[1] = BASE_FEE; slots[2] = 0; slots[3] = WAD; slots[4] = 0;\n slots[5] = initialX > 0 ? wdiv(initialY, initialX) : 100 * WAD;\n slots[6] = 950000000000000; slots[7] = 800000000000000000; slots[8] = 2000000000000000;\n slots[13] = 902500000000; slots[14] = slots[5]; slots[15] = 0; slots[9] = 0; slots[10] = 0; slots[11] = 0; slots[12] = 0;\n return (BASE_FEE, BASE_FEE);\n }\n\n function afterSwap(TradeInfo calldata trade) external override returns (uint256, uint256) {\n uint256 prevBidFee = slots[0]; uint256 prevAskFee = slots[1]; uint256 lastTs = slots[2];\n uint256 dirState = slots[3]; uint256 actEma = slots[4]; uint256 pHat = slots[5];\n uint256 sigmaHat = slots[6]; uint256 lambdaHat = slots[7]; uint256 sizeHat = slots[8];\n uint256 toxEma = slots[9]; uint256 stepTradeCount = slots[10];\n\n uint256 sigmaForFast = sigmaHat;\n uint256 fastHat = slots[14];\n uint256 uncertainty = slots[13];\n uint256 silent = trade.timestamp > lastTs ? trade.timestamp - lastTs : 0;\n bool isNewStep = trade.timestamp > lastTs;\n if (isNewStep) {\n uint256 elapsedRaw = trade.timestamp - lastTs;\n uint256 elapsed = elapsedRaw > ELAPSED_CAP ? ELAPSED_CAP : elapsedRaw;\n dirState = _decayCentered(dirState, DIR_DECAY, elapsed);\n actEma = wmul(actEma, _powWad(ACT_DECAY, elapsed));\n sizeHat = wmul(sizeHat, _powWad(SIZE_DECAY, elapsed));\n toxEma = wmul(toxEma, _powWad(TOX_DECAY, elapsed));\n if (stepTradeCount > 0 && elapsedRaw > 0) {\n uint256 lambdaInst = (stepTradeCount * WAD) / elapsedRaw;\n if (lambdaInst > LAMBDA_CAP) lambdaInst = LAMBDA_CAP;\n lambdaHat = wmul(lambdaHat, LAMBDA_DECAY) + wmul(lambdaInst, WAD - LAMBDA_DECAY);\n }\n uncertainty += wmul(sigmaForFast, sigmaForFast) * elapsedRaw;\n if (uncertainty > 100000000000000) uncertainty = 100000000000000;\n stepTradeCount = 0;\n }\n\n bool firstInStep = stepTradeCount == 0;\n uint256 spot = trade.reserveX > 0 ? wdiv(trade.reserveY, trade.reserveX) : pHat;\n if (pHat == 0) pHat = spot;\n\n uint256 feeUsed = trade.isBuy ? prevBidFee : prevAskFee;\n uint256 gamma = feeUsed < WAD ? WAD - feeUsed : 0;\n uint256 pImplied;\n if (gamma == 0) { pImplied = spot; }\n else { pImplied = trade.isBuy ? wmul(spot, gamma) : wdiv(spot, gamma); }\n\n // Silence: g silent steps mean fair stayed inside our last no-arb band.\n uint256 silW = 0;\n if (isNewStep && slots[16] > 0) {\n uint256 silG = trade.timestamp - lastTs - 1;\n if (silG > 4) silG = 4;\n if (silG >= 1 && prevAskFee < WAD) {\n silW = WAD - _powWad(925000000000000000, silG);\n uint256 sPrev = slots[16];\n uint256 bandMid = (wmul(sPrev, WAD - prevBidFee) + wdiv(sPrev, WAD - prevAskFee)) / 2;\n if (bandMid >= pHat) pHat = pHat + wmul(bandMid - pHat, silW);\n else pHat = pHat - wmul(pHat - bandMid, silW);\n }\n }\n\n {\n uint256 ret = pHat > 0 ? wdiv(absDiff(pImplied, pHat), pHat) : 0;\n uint256 alpha = firstInStep ? PHAT_ALPHA : 30000000000000000;\n uint256 prePhat = pHat;\n bool secondPrint = !firstInStep && stepTradeCount == 1;\n bool sameDir = false; bool oppDir = false;\n if (secondPrint) {\n bool up2 = pImplied >= pHat;\n uint256 d1 = slots[12];\n if (d1 != 0) { sameDir = (d1 == 1) == up2; oppDir = !sameDir; }\n if (sameDir) alpha = PHAT_ALPHA_SAME;\n }\n if (firstInStep) { slots[11] = pHat; slots[12] = pImplied >= pHat ? 1 : 2; }\n uint256 adaptiveGate = wmul(sigmaHat, GATE_SIGMA_MULT);\n if (adaptiveGate < MIN_GATE) adaptiveGate = MIN_GATE;\n if (silW > 0) {\n uint256 silScale = WAD - wmul(300000000000000000, silW);\n alpha = wmul(alpha, silScale);\n adaptiveGate = wmul(adaptiveGate, silScale);\n }\n if (ret <= adaptiveGate) { pHat = wmul(pHat, WAD - alpha) + wmul(pImplied, alpha); }\n if (oppDir && REVERT_U > 0) {\n uint256 pre = slots[11];\n if (pre > pHat) pHat = pHat + wmul(pre - pHat, REVERT_U);\n else pHat = pHat - wmul(pHat - pre, REVERT_U);\n }\n if (firstInStep) {\n if (ret > RET_CAP) ret = RET_CAP;\n sigmaHat = wmul(sigmaHat, SIGMA_DECAY) + wmul(ret, WAD - SIGMA_DECAY);\n }\n }\n\n // Interior retail routing equalizes fee-adjusted marginal prices.\n // Subsequent trades in a step cannot be the initial arbitrage trade.\n if (!firstInStep && feeUsed > 30 * BPS && gamma > 0) {\n uint256 normalSpot = trade.isBuy\n ? wdiv(wmul(spot, gamma), WAD - 30 * BPS)\n : wdiv(wmul(spot, WAD - 30 * BPS), gamma);\n pHat = wmul(pHat, 90 * WAD / 100) + wmul(normalSpot, 10 * WAD / 100);\n }\n\n {\n uint256 ret = fastHat > 0 ? wdiv(absDiff(pImplied, fastHat), fastHat) : 0;\n uint256 alpha;\n if (firstInStep) {\n uint256 processSigma = sigmaForFast;\n uint256 obsVar = uncertainty + wmul(processSigma, processSigma);\n uint256 probArb;\n uint256 z2 = wdiv(wmul(ret, ret), obsVar);\n uint256 density = _powWad(wdiv(WAD, WAD + z2 / 16), 8);\n uint256 sigmaObs = sqrt(obsVar * WAD);\n uint256 odds = wmul(density, wdiv(6700000000000000, sigmaObs));\n bool arbFlag = ret <= wmul(sigmaForFast, 1220000000000000000);\n uint256 prior = arbFlag ? 650000000000000000 : 400000000000000000;\n uint256 tr = trade.reserveY > 0 ? wdiv(trade.amountY, trade.reserveY) : 0;\n if (tr > 3000000000000000) prior = wmul(prior, 6 * WAD / 10);\n if (silent > 1) prior = wmul(prior, 8 * WAD / 10);\n odds = wmul(odds, wdiv(prior, WAD - prior));\n probArb = wdiv(odds, WAD + odds);\n alpha = wmul(probArb, 600000000000000000) + wmul(WAD - probArb, 80000000000000000);\n slots[15] = pImplied >= fastHat ? 1 : 2;\n uncertainty = wmul(uncertainty, WAD - alpha);\n } else {\n if ((slots[15] == 1) == (pImplied >= fastHat)) alpha = PHAT_ALPHA_RETAIL;\n }\n uint256 gate = wmul(sigmaHat, GATE_SIGMA_MULT);\n if (gate < MIN_GATE) gate = MIN_GATE;\n if (ret <= gate) fastHat = wmul(fastHat, WAD - alpha) + wmul(pImplied, alpha);\n slots[13] = uncertainty;\n }\n\n if (!firstInStep && feeUsed > 30 * BPS && gamma > 0) {\n uint256 normalObs = trade.isBuy\n ? wdiv(wmul(spot, gamma), WAD - 30 * BPS)\n : wdiv(wmul(spot, WAD - 30 * BPS), gamma);\n if ((slots[15] == 1) == (normalObs >= fastHat)) {\n fastHat = wmul(fastHat, 9 * WAD / 10) + wmul(normalObs, WAD / 10);\n }\n }\n slots[14] = fastHat;\n uint256 tradeRatio = trade.reserveY > 0 ? wdiv(trade.amountY, trade.reserveY) : 0;\n if (tradeRatio > TRADE_RATIO_CAP) tradeRatio = TRADE_RATIO_CAP;\n\n if (tradeRatio > SIGNAL_THRESHOLD) {\n uint256 push = tradeRatio * DIR_IMPACT_MULT;\n if (push > WAD / 4) push = WAD / 4;\n if (trade.isBuy) {\n dirState = dirState + push;\n if (dirState > 2 * WAD) dirState = 2 * WAD;\n } else {\n dirState = dirState > push ? dirState - push : 0;\n }\n actEma = wmul(actEma, ACT_BLEND_DECAY) + wmul(tradeRatio, WAD - ACT_BLEND_DECAY);\n sizeHat = wmul(sizeHat, SIZE_BLEND_DECAY) + wmul(tradeRatio, WAD - SIZE_BLEND_DECAY);\n if (sizeHat > WAD) sizeHat = WAD;\n }\n\n uint256 tox = pHat > 0 ? wdiv(absDiff(spot, pHat), pHat) : 0;\n if (tox > TOX_CAP) tox = TOX_CAP;\n toxEma = wmul(toxEma, TOX_BLEND_DECAY) + wmul(tox, WAD - TOX_BLEND_DECAY);\n uint256 toxSignal = toxEma;\n\n stepTradeCount = stepTradeCount + 1;\n if (stepTradeCount > STEP_COUNT_CAP) stepTradeCount = STEP_COUNT_CAP;\n\n uint256 flowSize = wmul(lambdaHat, sizeHat);\n uint256 fBase = BASE_FEE + wmul(SIGMA_COEF, sigmaHat) + wmul(LAMBDA_COEF, lambdaHat) + wmul(FLOW_SIZE_COEF, flowSize);\n uint256 fMid = fBase + wmul(TOX_COEF, toxSignal) + wmul(TOX_QUAD_COEF, wmul(toxSignal, toxSignal)) + wmul(ACT_COEF, actEma);\n fMid = fMid + wmul(SIGMA_TOX_COEF, wmul(sigmaHat, toxSignal));\n\n uint256 dirDev; bool sellPressure;\n if (dirState >= WAD) { dirDev = dirState - WAD; sellPressure = true; }\n else { dirDev = WAD - dirState; sellPressure = false; }\n\n uint256 skew = wmul(DIR_COEF, dirDev) + wmul(DIR_TOX_COEF, wmul(dirDev, toxSignal));\n uint256 bidFee; uint256 askFee;\n if (sellPressure) {\n bidFee = fMid + skew;\n askFee = fMid > skew ? fMid - skew : 0;\n } else {\n askFee = fMid + skew;\n bidFee = fMid > skew ? fMid - skew : 0;\n }\n\n {\n uint256 staleHat = wmul(pHat, 700000000000000000) + wmul(fastHat, 300000000000000000);\n uint256 staleTox = wdiv(absDiff(spot, staleHat), staleHat);\n if (staleTox > TOX_CAP) staleTox = TOX_CAP;\n uint256 staleShift = wmul(STALE_DIR_COEF, staleTox);\n uint256 attractShift = wmul(staleShift, STALE_ATTRACT_FRAC);\n if (spot >= staleHat) {\n bidFee = bidFee + staleShift;\n askFee = askFee > attractShift ? askFee - attractShift : 0;\n } else {\n askFee = askFee + staleShift;\n bidFee = bidFee > attractShift ? bidFee - attractShift : 0;\n }\n }\n\n {\n bool tradeAligned = (trade.isBuy && spot >= pHat) || (!trade.isBuy && spot < pHat);\n if (tradeAligned) {\n uint256 tradeBoost = wmul(TRADE_TOX_BOOST, tradeRatio);\n if (trade.isBuy) { bidFee = bidFee + tradeBoost; }\n else { askFee = askFee + tradeBoost; }\n }\n }\n\n if (sellPressure) {\n bidFee = clampFee(_compressTailWithSlope(bidFee, TAIL_SLOPE_PROTECT));\n askFee = clampFee(_compressTailWithSlope(askFee, TAIL_SLOPE_ATTRACT));\n } else {\n askFee = clampFee(_compressTailWithSlope(askFee, TAIL_SLOPE_PROTECT));\n bidFee = clampFee(_compressTailWithSlope(bidFee, TAIL_SLOPE_ATTRACT));\n }\n\n slots[0] = bidFee; slots[1] = askFee; slots[2] = trade.timestamp;\n slots[3] = dirState; slots[4] = actEma; slots[5] = pHat;\n slots[6] = sigmaHat; slots[7] = lambdaHat; slots[8] = sizeHat;\n slots[9] = toxEma; slots[10] = stepTradeCount; slots[16] = spot;\n\n return (bidFee, askFee);\n }\n\n function _compressTailWithSlope(uint256 fee, uint256 slope) internal pure returns (uint256) {\n if (fee <= TAIL_KNEE) return fee;\n return TAIL_KNEE + wmul(fee - TAIL_KNEE, slope);\n }\n\n function _powWad(uint256 factor, uint256 exp) internal pure returns (uint256 result) {\n result = WAD;\n while (exp > 0) {\n if (exp & 1 == 1) result = wmul(result, factor);\n factor = wmul(factor, factor);\n exp >>= 1;\n }\n }\n\n function _decayCentered(uint256 centered, uint256 decayFactor, uint256 elapsed) internal pure returns (uint256) {\n uint256 mul = _powWad(decayFactor, elapsed);\n if (centered >= WAD) { return WAD + wmul(centered - WAD, mul); }\n uint256 below = wmul(WAD - centered, mul);\n return below < WAD ? WAD - below : 0;\n }\n\n function getName() external pure override returns (string memory) { return \"no_cubic\"; }\n}\n", "sha256": "508ae3f24d0f042dd621ed7a8f7e90ba35457b1d3c252d980b91a6467648bbec", "b_sha256": "218426004abed3b6cb69f4ef133fea8e4789ddbeae37bd11e94e5ffc5f2a77cb", "np2_sha256": "51f1c1a9d4999ee460eb8bbc66880da8074b173399a4f5d71f96671482e18ac0", "seeds": "2960000..2963999", "paired_np2": { "n": 4000, "mean_diff": 0.6325102568045465, "se": 0.014536994606024449, "worst": [ { "seed": 2961301, "cand_edge": 723.7278727478921, "np2_edge": 727.9655049947564, "diff": -4.237632246864337 }, { "seed": 2961852, "cand_edge": 592.7672375024, "np2_edge": 596.4331270688994, "diff": -3.665889566499345 }, { "seed": 2962092, "cand_edge": 566.3670986353551, "np2_edge": 570.0296718295641, "diff": -3.662573194209017 }, { "seed": 2961439, "cand_edge": 556.827820691766, "np2_edge": 560.3182464881531, "diff": -3.4904257963871714 }, { "seed": 2963631, "cand_edge": 480.1411400080195, "np2_edge": 483.2892298540423, "diff": -3.148089846022799 } ] }, "paired_b": { "n": 4000, "mean_diff": 0.19169069369265052, "se": 0.026978900173035482 }, "paired_b_vs_np2": { "n": 4000, "mean_diff": 0.4408195631118961, "se": 0.02826200013829918 }, "means": { "cand": 526.4794945697212, "np2": 525.8469843129167, "b": 526.2878038760285 }, "seconds_per_sim": { "cand": 0.20942312413454056, "np2": 0.14187069684267045, "b": 0.1929743916988373 }, "validate_ok": true, "blocked": null, "notes": [ "Simulator benedictbrady/amm-challenge @6b6921f8 built with the item's setup script (Linux x86_64); amm-match validate passed for cand, NP2 and B.", "NP2 rebuilt from TWO + NP block gives sha256 51f1c1a9d4999ee460eb8bbc66880da8074b173399a4f5d71f96671482e18ac0, and the harness scores it at 526.1155722459862 on seeds 0..999, which matches the objective's 526.1156. I did not run the CH 525.525882178 calibration separately; the exact NP2 match checks the same harness.", "B's ```solidity block extracted as built hashes to 218426004abed3b6cb69f4ef133fea8e4789ddbeae37bd11e94e5ffc5f2a77cb (matches 21842600...).", "Measurement: per seed s, numpy default_rng(s) draws size, rate, sigma; SimulationConfig seed=s with BASELINE settings. run_batch(X, VanillaStrategy, cfgs, 8) is called separately for X in {cand, NP2, B}, 20 seeds per call, and cand never faces NP2. Diffs are paired by seed with se = sd(ddof=1)/sqrt(n). The block was run once per strategy and never used for anything else.", "Timing: a pilot on NP2 gave 0.124 s/sim, below 0.2, so the full 4000-seed block was run. Under machine load the cand and B runs later averaged 0.19-0.22 s/sim (cand overall 0.209, over 0.2). 4000 seeds were still run and reported, not the shorter fallback.", "L: only the slow-path line became `uint256 alpha = firstInStep ? PHAT_ALPHA : 30000000000000000;`. The fast estimator's later-print alpha remains PHAT_ALPHA_RETAIL (0.06).", "S, as I read it: slots[16] holds our post-trade spot s, written at the end of each afterSwap. At a new step's first print, g = min(elapsed-1, 4) with elapsed = timestamp - lastTs. If g >= 1, s > 0 and prevAskFee < 1, then w = 1 - 0.925^g, c = (s*(1-prevBidFee) + s/(1-prevAskFee))/2 using the fees posted after the previous trade (slots[0], slots[1]), and slow pHat += w(c - pHat) is applied before the slow update. The slow ret and sigma update then use the shifted pHat. That print's slow alpha and adaptive gate (after the MIN_GATE floor) are each multiplied by 1 - 0.30w. The fast estimator (fastHat) is untouched.", "Deviation: writing slots[16] in afterInitialize ran past the 250000 gas limit for afterInitialize (OutOfGas), so slots[16] is not set there. S is skipped until the first trade has stored a spot.", "Result: cand beats NP2 by +0.633 +/- 0.015 and beats B by +0.192 +/- 0.027 on this block. In the same run B beats NP2 by +0.441 +/- 0.028. This is far below the +5.8 top-10 target.", "Not done: N (next-mix-a) was excluded as the brief asks, and its artifact was not read." ] }