WIP

Co-authored-by: Max <[email protected]>

packages/nimiq-vts/package.json

@@ -39,11 +39,13 @@
     "prepublishOnly": "nr build",
     "release": "bumpp && npm publish",
     "start": "esno src/index.ts",
-    "typecheck": "tsc --noEmit"
+    "typecheck": "tsc --noEmit",
+    "test": "vitest"
   },
   "dependencies": {
     "defu": "^6.1.4",
-    "nimiq-rpc-client-ts": "^0.3.0"
+    "nimiq-rpc-client-ts": "^0.3.0",
+    "vitest": "^1.6.0"
   },
   "devDependencies": {
     "@antfu/ni": "^0.21.12",

packages/nimiq-vts/src/score.test.ts

@@ -0,0 +1,15 @@
+import { describe, expect, it, beforeEach } from 'vitest'
+import { getLiveness } from './score'
+
+describe('should compute livenes correctly', () => {
+  const fromEpoch = 3075210
+  const toEpoch = 5062410
+  const blocksPerEpoch = 43200
+  const activeEpochBlockNumbers = Array.from({ length: Math.floor((toEpoch - fromEpoch) / blocksPerEpoch) }, (_, i) => fromEpoch + i * blocksPerEpoch)
+  const weightFactor = 0.5
+
+  it('exported', () => {
+    const liveness = getLiveness({fromEpoch, toEpoch, weightFactor, activeEpochBlockNumbers, blocksPerEpoch })
+    expect(liveness).toBeGreaterThan(0.5)
+  })
+})

packages/nimiq-vts/src/score.ts

@@ -9,28 +9,34 @@ export function getSize({ balance, threshold, steepness, totalBalance }: ScorePa
   return s
 }
 
+// TODO: active epoch numbers convert to binary array
 export function getLiveness({ activeEpochBlockNumbers, blocksPerEpoch, fromEpoch, toEpoch, weightFactor }: ScoreParams['liveness']) {
   if (!activeEpochBlockNumbers || !fromEpoch || !toEpoch || !weightFactor || !blocksPerEpoch)
-    throw new Error("Active epoch block numbers, from epoch, to epoch, blocks per epoch, or weight factor is not set")
+    throw new Error(`Invalid params: ${JSON.stringify({ activeEpochBlockNumbers, blocksPerEpoch, fromEpoch, toEpoch, weightFactor })}`)
   if (fromEpoch === -1 || toEpoch === -1 || activeEpochBlockNumbers.length === 0)
     throw new Error(`fromEpoch, toEpoch, or activeEpochBlockNumbers is not set: ${fromEpoch}, ${toEpoch}, ${activeEpochBlockNumbers}`)
+  if (toEpoch - fromEpoch + 1 <= 0) 
+    throw new Error(`Invalid epoch range. fromEpoch: ${fromEpoch}, toEpoch: ${toEpoch}`)
 
-  const n = toEpoch - fromEpoch + 1; // Total number of epochs in the window
-  if (n <= 0) throw new Error('Invalid epoch range');
+  let weightedSum = 0
+  let weightTotal = 0
 
-  let weightedSum = 0;
-  let weightTotal = 0;
-
-  for (let i = toEpoch; i >= fromEpoch; i--) {
-    const isActive = activeEpochBlockNumbers.includes(i) ? 1 : 0;
-    const weight = 1 - weightFactor * (i - fromEpoch) / (toEpoch - fromEpoch);
-    weightedSum += weight * isActive;
-    weightTotal += weight;
+  const n = toEpoch - fromEpoch // Total number of epochs in the window
+  const indexToBlockNumber = (i: number) => fromEpoch + i * blocksPerEpoch
+  console.log({ fromEpoch, toEpoch, weightFactor, n })
+  for (let i = 0; i <= n; i++) {
+    const index = indexToBlockNumber(i)
+    const isActive = activeEpochBlockNumbers.indexOf(index) ? 1 : 0
+    const weight = 1 - weightFactor * index / n
+    weightedSum += weight * isActive
+    weightTotal += weight
+    if(i < 20)
+      console.log(JSON.stringify({ i, isActive, weight, weightedSum, weightTotal, x: weightFactor * i / n },null, 2))
   }
-  if (weightTotal === 0) throw new Error('Weight total is zero, cannot divide by zero');
+  if (weightTotal === 0) throw new Error('Weight total is zero, cannot divide by zero')
 
-  const movingAverage = weightedSum / weightTotal;
-  const liveness = -Math.pow(movingAverage, 2) + 2 * movingAverage;
+  const movingAverage = weightedSum / weightTotal
+  const liveness = -Math.pow(movingAverage, 2) + 2 * movingAverage
 
   return liveness
 }

packages/nimiq-vts/src/types.ts

@@ -4,6 +4,7 @@ export type ScoreParams = {
   reliability?: {}
 }
 export type ActivityEpoch = { validator: string, assigned: number, missed: number }[]
+// TODO: rename ValidatorActivity to be more descriptive
 export type ValidatorActivity = Record<string /* address */, { activeEpochBlockNumbers: number[], validatorId: number, balance: number }>
 export type EpochActivity = Record<number /* Election block number */, ActivityEpoch>
 export type ScoreValues = { liveness: number, reliability: number, size: number, total: number }

packages/nimiq-vts/src/utils.ts

@@ -25,6 +25,7 @@ export async function getRange(client: Client, options?: GetRangeOptions): Promi
     if (errorCurrentEpoch || !currentEpoch) throw new Error(errorCurrentEpoch?.message || 'No current epoch')
     toEpochIndex = currentEpoch - 1
   }
+  // Don't go back more than the block after the genesis block
   const fromEpochIndex = Math.max(1, toEpochIndex - epochsCount)
 
   // Convert indexes to election blocks