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Tia Lim 0f0f728166 Format faiss Python files with black (line length 80) (#5349)
Summary:
Pull Request resolved: https://github.com/facebookresearch/faiss/pull/5349

# this is a no-op change

Ran `black -l 80` over all tracked Python files under `fbcode/faiss/`, using line length 80 to match faiss's documented coding style (`CONTRIBUTING.md`: "80 character line length (both for C++ and Python)"). 172 files were reformatted; 28 were already compliant.

This is a pure-formatting change. `black` runs its AST-equivalence safety check on every file, so no identifiers, string/numeric values, operators, or control flow were altered — only whitespace, indentation, line wrapping, blank lines, trailing commas, and string-quote normalization (single to double quotes).

`fbcode/faiss/` is intentionally excluded from Meta's standard Python autoformatter (`arc f` / `arc lint -a` report no formatter for these paths) because it mirrors to public GitHub, so the Python had drifted out of any consistent style. The C++ is already clang-format-clean (0 of 807 files change), so this effort is Python-only. This diff brings the Python to canonical `black` formatting.

Excluded `demos/index_pq_flat_separate_codes_from_codebook.py`: it contains a Jupyter `!rm` shell-magic line and is not valid Python, so `black` cannot parse it.

This is the base of a 3-diff stack: (1) this black reformat; (2) `.flake8` alignment (max-line-length 80 + black-compatible ignores E203/W503); (3) genuine lint fixes (F401/F403/F841/B011).

Reviewed By: mnorris11

Differential Revision: D109736099

fbshipit-source-id: 9a054635766ed11aa3760a788395babd3d198abf
2026-06-29 17:29:05 -07:00

76 lines
2.3 KiB
Python

# Copyright (c) Meta Platforms, Inc. and affiliates.
#
# This source code is licensed under the MIT license found in the
# LICENSE file in the root directory of this source tree.
"""
This demonstrates how to reproduce the QINCo paper results using the Faiss
QINCo implementation. The code loads the reference model because training
is not implemented in Faiss.
Prepare the data with
cd /tmp
# get the reference qinco code
git clone https://github.com/facebookresearch/Qinco.git
# get the data
wget https://dl.fbaipublicfiles.com/QINCo/datasets/bigann/bigann1M.bvecs
# get the model
wget https://dl.fbaipublicfiles.com/QINCo/models/bigann_8x8_L2.pt
"""
from faiss.contrib.vecs_io import bvecs_mmap
import sys
import time
import torch
import faiss
# make sure pickle deserialization will work
sys.path.append("/tmp/Qinco")
with torch.no_grad():
qinco = torch.load("/tmp/bigann_8x8_L2.pt", weights_only=False)
qinco.eval()
# print(qinco)
if True:
torch.set_num_threads(1)
faiss.omp_set_num_threads(1)
x_base = bvecs_mmap("/tmp/bigann1M.bvecs")[:1000].astype("float32")
x_scaled = torch.from_numpy(x_base) / qinco.db_scale
t0 = time.time()
codes, _ = qinco.encode(x_scaled)
x_decoded_scaled = qinco.decode(codes)
print(f"Pytorch encode {time.time() - t0:.3f} s")
# multi-thread: 1.13s, single-thread: 7.744
x_decoded = x_decoded_scaled.numpy() * qinco.db_scale
err = ((x_decoded - x_base) ** 2).sum(1).mean()
print("MSE=", err) # = 14211.956, near the L=2 result in Fig 4 of the paper
qinco2 = faiss.QINCo(qinco)
t0 = time.time()
codes2 = qinco2.encode(faiss.Tensor2D(x_scaled))
x_decoded2 = qinco2.decode(codes2).numpy() * qinco.db_scale
print(f"Faiss encode {time.time() - t0:.3f} s")
# multi-thread: 3.2s, single thread: 7.019
# these tests don't work because there are outlier encodings
# np.testing.assert_array_equal(codes.numpy(), codes2.numpy())
# np.testing.assert_allclose(x_decoded, x_decoded2)
ndiff = (codes.numpy() != codes2.numpy()).sum() / codes.numel()
assert ndiff < 0.01
ndiff = (((x_decoded - x_decoded2) ** 2).sum(1) > 1e-5).sum()
assert ndiff / len(x_base) < 0.01
err = ((x_decoded2 - x_base) ** 2).sum(1).mean()
print("MSE=", err) # = 14213.551