/**
 * Embedding Normalization Utilities
 *
 * Features:
 * - L2 (Euclidean) normalization
 * - L1 (Manhattan) normalization
 * - Min-max normalization
 * - Z-score standardization
 * - Batch normalization
 */
/**
 * L2 (Euclidean) normalize embedding to unit length
 * Most common for cosine similarity
 *
 * @param embedding - Input embedding vector
 * @param epsilon - Small value to prevent division by zero
 * @returns Normalized embedding with ||v|| = 1
 */
export function l2Normalize(embedding, epsilon = 1e-12) {
    const result = embedding instanceof Float32Array
        ? new Float32Array(embedding.length)
        : new Float32Array(embedding.length);
    // Calculate L2 norm (Euclidean length)
    let sumSquares = 0;
    for (let i = 0; i < embedding.length; i++) {
        sumSquares += embedding[i] * embedding[i];
    }
    const norm = Math.sqrt(sumSquares);
    const scale = norm > epsilon ? 1 / norm : 0;
    // Normalize
    for (let i = 0; i < embedding.length; i++) {
        result[i] = embedding[i] * scale;
    }
    return result;
}
/**
 * L2 normalize embedding in-place (modifies original array)
 */
export function l2NormalizeInPlace(embedding, epsilon = 1e-12) {
    let sumSquares = 0;
    for (let i = 0; i < embedding.length; i++) {
        sumSquares += embedding[i] * embedding[i];
    }
    const norm = Math.sqrt(sumSquares);
    const scale = norm > epsilon ? 1 / norm : 0;
    for (let i = 0; i < embedding.length; i++) {
        embedding[i] *= scale;
    }
    return embedding;
}
/**
 * L1 (Manhattan) normalize embedding
 * Sum of absolute values = 1
 */
export function l1Normalize(embedding, epsilon = 1e-12) {
    const result = new Float32Array(embedding.length);
    // Calculate L1 norm (sum of absolute values)
    let sumAbs = 0;
    for (let i = 0; i < embedding.length; i++) {
        sumAbs += Math.abs(embedding[i]);
    }
    const scale = sumAbs > epsilon ? 1 / sumAbs : 0;
    for (let i = 0; i < embedding.length; i++) {
        result[i] = embedding[i] * scale;
    }
    return result;
}
/**
 * Min-max normalize embedding to [0, 1] range
 */
export function minMaxNormalize(embedding, epsilon = 1e-12) {
    const result = new Float32Array(embedding.length);
    // Find min and max
    let min = Infinity;
    let max = -Infinity;
    for (let i = 0; i < embedding.length; i++) {
        if (embedding[i] < min)
            min = embedding[i];
        if (embedding[i] > max)
            max = embedding[i];
    }
    const range = max - min;
    const scale = range > epsilon ? 1 / range : 0;
    for (let i = 0; i < embedding.length; i++) {
        result[i] = (embedding[i] - min) * scale;
    }
    return result;
}
/**
 * Z-score standardize embedding (mean=0, std=1)
 */
export function zScoreNormalize(embedding, epsilon = 1e-12) {
    const result = new Float32Array(embedding.length);
    const n = embedding.length;
    // Calculate mean
    let sum = 0;
    for (let i = 0; i < n; i++) {
        sum += embedding[i];
    }
    const mean = sum / n;
    // Calculate standard deviation
    let sumSquaredDiff = 0;
    for (let i = 0; i < n; i++) {
        const diff = embedding[i] - mean;
        sumSquaredDiff += diff * diff;
    }
    const std = Math.sqrt(sumSquaredDiff / n);
    const scale = std > epsilon ? 1 / std : 0;
    // Standardize
    for (let i = 0; i < n; i++) {
        result[i] = (embedding[i] - mean) * scale;
    }
    return result;
}
/**
 * Normalize embedding using specified method
 */
export function normalize(embedding, options = {}) {
    const { type = 'l2', epsilon = 1e-12, inPlace = false } = options;
    if (type === 'none') {
        return embedding instanceof Float32Array
            ? embedding
            : new Float32Array(embedding);
    }
    if (inPlace && embedding instanceof Float32Array && type === 'l2') {
        return l2NormalizeInPlace(embedding, epsilon);
    }
    switch (type) {
        case 'l2':
            return l2Normalize(embedding, epsilon);
        case 'l1':
            return l1Normalize(embedding, epsilon);
        case 'minmax':
            return minMaxNormalize(embedding, epsilon);
        case 'zscore':
            return zScoreNormalize(embedding, epsilon);
        default:
            return l2Normalize(embedding, epsilon);
    }
}
/**
 * Batch normalize multiple embeddings
 */
export function normalizeBatch(embeddings, options = {}) {
    return embeddings.map(emb => normalize(emb, options));
}
/**
 * Calculate L2 norm of embedding
 */
export function l2Norm(embedding) {
    let sumSquares = 0;
    for (let i = 0; i < embedding.length; i++) {
        sumSquares += embedding[i] * embedding[i];
    }
    return Math.sqrt(sumSquares);
}
/**
 * Check if embedding is already normalized (L2 norm ≈ 1)
 */
export function isNormalized(embedding, tolerance = 1e-6) {
    const norm = l2Norm(embedding);
    return Math.abs(norm - 1) < tolerance;
}
/**
 * Center embeddings by subtracting mean across batch
 * Useful for improving similarity metrics
 */
export function centerEmbeddings(embeddings) {
    if (embeddings.length === 0)
        return [];
    const dim = embeddings[0].length;
    const n = embeddings.length;
    // Calculate mean for each dimension
    const mean = new Float32Array(dim);
    for (const emb of embeddings) {
        for (let i = 0; i < dim; i++) {
            mean[i] += emb[i];
        }
    }
    for (let i = 0; i < dim; i++) {
        mean[i] /= n;
    }
    // Subtract mean from each embedding
    return embeddings.map(emb => {
        const centered = new Float32Array(dim);
        for (let i = 0; i < dim; i++) {
            centered[i] = emb[i] - mean[i];
        }
        return centered;
    });
}
//# sourceMappingURL=normalization.js.map