export function normalizeRelevance(relevance) {
if (!relevance) {
return new Map();
}
if (relevance instanceof Map) {
return relevance;
}
if (relevance instanceof Set) {
const map = new Map();
for (const value of relevance) {
map.set(value, 1);
}
return map;
}
if (Array.isArray(relevance)) {
const map = new Map();
for (const value of relevance) {
if (value && typeof value === 'object' && 'sha' in value) {
const sha = value.sha;
const gain = typeof value.gain === 'number' ? value.gain : 1;
map.set(sha, gain);
} else if (typeof value === 'string') {
map.set(value, 1);
}
}
return map;
}
if (typeof relevance === 'object') {
const map = new Map();
for (const [key, value] of Object.entries(relevance)) {
if (typeof value === 'number') {
map.set(key, value);
} else if (value) {
map.set(key, 1);
}
}
return map;
}
return new Map();
}
export function precisionAt(results, relevance, k = 1) {
if (!Array.isArray(results) || results.length === 0 || k <= 0) {
return 0;
}
const relevanceMap = normalizeRelevance(relevance);
if (relevanceMap.size === 0) {
return 0;
}
const topK = results.slice(0, k);
const relevantHits = topK.filter(result => relevanceMap.has(result.sha)).length;
return relevantHits / k;
}
export function reciprocalRankAt(results, relevance, k = 10) {
if (!Array.isArray(results) || results.length === 0 || k <= 0) {
return 0;
}
const relevanceMap = normalizeRelevance(relevance);
if (relevanceMap.size === 0) {
return 0;
}
const topK = results.slice(0, k);
for (let index = 0; index < topK.length; index++) {
const candidate = topK[index];
if (relevanceMap.has(candidate.sha)) {
return 1 / (index + 1);
}
}
return 0;
}
function computeDcg(results, relevanceMap, k) {
let dcg = 0;
for (let index = 0; index < Math.min(k, results.length); index++) {
const candidate = results[index];
const gain = relevanceMap.get(candidate.sha) || 0;
if (gain <= 0) {
continue;
}
const denominator = Math.log2(index + 2);
dcg += (Math.pow(2, gain) - 1) / denominator;
}
return dcg;
}
export function ndcgAt(results, relevance, k = 10) {
if (!Array.isArray(results) || results.length === 0 || k <= 0) {
return 0;
}
const relevanceMap = normalizeRelevance(relevance);
if (relevanceMap.size === 0) {
return 0;
}
const dcg = computeDcg(results, relevanceMap, k);
if (dcg === 0) {
return 0;
}
const idealGains = Array.from(relevanceMap.values())
.filter(value => value > 0)
.sort((a, b) => b - a);
const idealResults = idealGains.map((gain, index) => ({ sha: `ideal-${index}`, gain }));
const idealMap = new Map(idealResults.map(item => [item.sha, item.gain]));
const idealDcg = computeDcg(
idealResults,
idealMap,
Math.min(k, idealResults.length)
);
if (idealDcg === 0) {
return 0;
}
return dcg / idealDcg;
}
export function averageMetric(values) {
if (!Array.isArray(values) || values.length === 0) {
return 0;
}
const sum = values.reduce((acc, value) => acc + value, 0);
return sum / values.length;
}
