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Improve Random Sampling challenge creation #394

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b980c23
improve challenge creation
Jun 13, 2025
da286cc
Add more tests to RS Storage and adapt old ones
Jun 13, 2025
f95a782
fix tests
Jun 13, 2025
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178 changes: 178 additions & 0 deletions abi/RandomSamplingStorage.json
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,16 @@
"internalType": "uint16",
"name": "_proofingPeriodDurationInBlocks",
"type": "uint16"
},
{
"internalType": "uint16",
"name": "_challengeRecencyFactor",
"type": "uint16"
},
{
"internalType": "uint8",
"name": "_bfsIterations",
"type": "uint8"
}
],
"stateMutability": "nonpayable",
Expand Down Expand Up @@ -87,6 +97,44 @@
"name": "AllNodesEpochScoreAdded",
"type": "event"
},
{
"anonymous": false,
"inputs": [
{
"indexed": false,
"internalType": "uint8",
"name": "oldBfsIterations",
"type": "uint8"
},
{
"indexed": false,
"internalType": "uint8",
"name": "newBfsIterations",
"type": "uint8"
}
],
"name": "BfsIterationsUpdated",
"type": "event"
},
{
"anonymous": false,
"inputs": [
{
"indexed": false,
"internalType": "uint16",
"name": "oldChallengeRecencyFactor",
"type": "uint16"
},
{
"indexed": false,
"internalType": "uint16",
"name": "newChallengeRecencyFactor",
"type": "uint16"
}
],
"name": "ChallengeRecencyFactorUpdated",
"type": "event"
},
{
"anonymous": false,
"inputs": [
Expand Down Expand Up @@ -305,6 +353,32 @@
"stateMutability": "view",
"type": "function"
},
{
"inputs": [],
"name": "DEFAULT_BFS_ITERATIONS",
"outputs": [
{
"internalType": "uint8",
"name": "",
"type": "uint8"
}
],
"stateMutability": "view",
"type": "function"
},
{
"inputs": [],
"name": "MAX_CHALLENGE_RECENCY_FACTOR",
"outputs": [
{
"internalType": "uint16",
"name": "",
"type": "uint16"
}
],
"stateMutability": "view",
"type": "function"
},
{
"inputs": [
{
Expand Down Expand Up @@ -509,6 +583,32 @@
"stateMutability": "view",
"type": "function"
},
{
"inputs": [],
"name": "bfsIterations",
"outputs": [
{
"internalType": "uint8",
"name": "",
"type": "uint8"
}
],
"stateMutability": "view",
"type": "function"
},
{
"inputs": [],
"name": "challengeRecencyFactor",
"outputs": [
{
"internalType": "uint16",
"name": "",
"type": "uint16"
}
],
"stateMutability": "view",
"type": "function"
},
{
"inputs": [],
"name": "chronos",
Expand Down Expand Up @@ -661,6 +761,45 @@
"stateMutability": "view",
"type": "function"
},
{
"inputs": [],
"name": "getBfsIterations",
"outputs": [
{
"internalType": "uint8",
"name": "",
"type": "uint8"
}
],
"stateMutability": "view",
"type": "function"
},
{
"inputs": [],
"name": "getChallengeRecencyFactor",
"outputs": [
{
"internalType": "uint16",
"name": "",
"type": "uint16"
}
],
"stateMutability": "view",
"type": "function"
},
{
"inputs": [],
"name": "getDefaultBfsIterations",
"outputs": [
{
"internalType": "uint8",
"name": "",
"type": "uint8"
}
],
"stateMutability": "pure",
"type": "function"
},
{
"inputs": [
{
Expand Down Expand Up @@ -810,6 +949,19 @@
"stateMutability": "view",
"type": "function"
},
{
"inputs": [],
"name": "getMaxChallengeRecencyFactor",
"outputs": [
{
"internalType": "uint16",
"name": "",
"type": "uint16"
}
],
"stateMutability": "pure",
"type": "function"
},
{
"inputs": [
{
Expand Down Expand Up @@ -1175,6 +1327,32 @@
"stateMutability": "nonpayable",
"type": "function"
},
{
"inputs": [
{
"internalType": "uint8",
"name": "newBfsIterations",
"type": "uint8"
}
],
"name": "setBfsIterations",
"outputs": [],
"stateMutability": "nonpayable",
"type": "function"
},
{
"inputs": [
{
"internalType": "uint16",
"name": "newChallengeRecencyFactor",
"type": "uint16"
}
],
"name": "setChallengeRecencyFactor",
"outputs": [],
"stateMutability": "nonpayable",
"type": "function"
},
{
"inputs": [
{
Expand Down
116 changes: 69 additions & 47 deletions contracts/RandomSampling.sol
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -293,76 +293,98 @@ contract RandomSampling is INamed, IVersioned, ContractStatus, IInitializable {
}

/**
* @dev BFS approach to finding an active knowledge collection
* @param randomSeed Random seed for picking a collection from current range
* @param start Start of the range (inclusive)
* @param end End of the range (inclusive)
* @param currentEpoch Current epoch to check collection activity against
* @return knowledgeCollectionId ID of an active knowledge collection, or 0 if none found
* @dev Adaptive BFS search for an active collection.
* challengeRecencyFactor 5,000 → 50% chance to pop newer/older half first
* 10,000→ always pop newer half first
* bfsIterations user-controllable gas/latency guard (default: 50)
*/
function _findActiveKnowledgeCollection(
bytes32 randomSeed,
uint256 start,
uint256 end,
uint256 currentEpoch
) internal view returns (uint256) {
// Queue using fixed array - [start1, end1, start2, end2, ...]
uint256[100] memory queue; // Can hold 50 ranges max
uint8 queueStart = 0; // Front of queue
uint8 queueEnd = 0; // Back of queue

// Push initial range
uint8 bfsIterations = randomSamplingStorage.getBfsIterations();
uint8 itCap = bfsIterations == 0 ? randomSamplingStorage.getDefaultBfsIterations() : bfsIterations;
uint16 challengeRecencyFactor = randomSamplingStorage.getChallengeRecencyFactor();
uint16 maxChallengeRecencyFactor = randomSamplingStorage.getMaxChallengeRecencyFactor();

// Calculate proper queue size: we process at most itCap ranges, each can split into 2
// Maximum queue size = initial range + ranges from splitting = 2 * (itCap + 1) slots
uint256 queueSize = 2 * (uint256(itCap) + 1);
uint256[] memory queue = new uint256[](queueSize);

uint16 queueStart = 0; // front index
uint16 queueEnd = 0; // back index
queue[queueEnd++] = start;
queue[queueEnd++] = end;

bytes32 currentRandom = randomSeed;
bytes32 currentRandomSeed = randomSeed;
uint8 iterations = 0;

while (queueStart < queueEnd && iterations < 50) {
// Pop range from front of queue (BFS behavior)
uint256 currentStart = queue[queueStart++];
uint256 currentEnd = queue[queueStart++];

// Pick random collection from current range
uint256 randomKcId = currentStart + (uint256(currentRandom) % (currentEnd - currentStart + 1));

// Check if this collection is active
if (currentEpoch <= knowledgeCollectionStorage.getEndEpoch(randomKcId)) {
return randomKcId;
}
while (queueStart < queueEnd && iterations < itCap) {
uint256 lo = queue[queueStart++];
uint256 hi = queue[queueStart++];
uint256 span = hi - lo + 1;

// If single element and not active, continue to next range
if (currentStart == currentEnd) {
currentRandom = keccak256(abi.encodePacked(currentRandom));
unchecked {
iterations++;
uint256 pick;
uint256 roll = uint256(currentRandomSeed);
if (challengeRecencyFactor == 0) {
pick = lo + (roll % span); // uniform
} else {
// 1) decide which half we favour this iteration
bool favourNewer = (roll % maxChallengeRecencyFactor) < challengeRecencyFactor;
uint256 mid = lo + (span >> 1);

if (favourNewer) {
// sample uniformly from newer half [mid+1,hi]
uint256 newerSpan = hi - mid;
pick = (newerSpan == 0) ? hi : mid + 1 + (roll % newerSpan);
} else {
// sample from older half [lo,mid]
uint256 olderSpan = mid - lo + 1;
pick = lo + (roll % olderSpan);
}
continue;
}

// Split range and push both halves to back of queue (BFS order)
uint256 mid = currentStart + (currentEnd - currentStart) / 2;
if (currentEpoch <= knowledgeCollectionStorage.getEndEpoch(pick)) {
return pick;
}

if (queueEnd < 96) {
// Leave room for both ranges
// Always push left half first, then right half (consistent BFS)
if (currentStart <= mid) {
queue[queueEnd++] = currentStart;
queue[queueEnd++] = mid;
}
if (mid + 1 <= currentEnd) {
queue[queueEnd++] = mid + 1;
queue[queueEnd++] = currentEnd;
// not active → split and enqueue, order depends on challengeRecencyFactor
if (lo != hi && queueEnd <= queueSize - 4) {
// Ensure we have space for 2 ranges (4 slots)
uint256 mid = lo + (span >> 1);
bool newerFirst = (uint256(currentRandomSeed) >> 128) % maxChallengeRecencyFactor <
challengeRecencyFactor;

if (newerFirst) {
if (mid + 1 <= hi) {
queue[queueEnd++] = mid + 1;
queue[queueEnd++] = hi;
}
if (lo <= mid) {
queue[queueEnd++] = lo;
queue[queueEnd++] = mid;
}
} else {
if (lo <= mid) {
queue[queueEnd++] = lo;
queue[queueEnd++] = mid;
}
if (mid + 1 <= hi) {
queue[queueEnd++] = mid + 1;
queue[queueEnd++] = hi;
}
}
}

currentRandom = keccak256(abi.encodePacked(currentRandom));
currentRandomSeed = keccak256(abi.encodePacked(currentRandomSeed));
unchecked {
iterations++;
++iterations;
}
}

return 0; // No active collection found
return 0; // no active collection found
}

function calculateNodeScore(uint72 identityId) public view returns (uint256) {
Expand Down
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