import faiss
import numpy as np
import time

dim = 1536  # OpenAI/text-embedding-ada-002
num_vectors = 10_000
np.random.seed(42)
vectors = np.random.randn(num_vectors, dim).astype(np.float32)

index = faiss.IndexFlatL2(dim)
index.add(vectors)

query = np.random.randn(1, dim).astype(np.float32)

start = time.time()
D, I = index.search(query, k=5)
latency = (time.time() - start) * 1000

print(f"FAISS top-5 retrieval latency: {latency:.2f} ms")