Files
faiss/tests/test_fast_scan.py
T
Michael Norris ec94295adc Bound the fast scan LUT scale by the accumulated sum (#5658)
Summary:
Pull Request resolved: https://github.com/facebookresearch/faiss/pull/5658

A fast scan kernel sums `M` uint8 table entries into a uint16 that can wrap around to 0. The scale that quantizes the table must therefore bound the whole sum that gets accumulated, not only one entry. Seven call sites each held their own copy of that rule. Only four applied it.

This adds `quantize_lut::fastscan_lut_scale` and routes all seven through it. The bound also reserves a margin for `round_tab`, which rounds half up, so `n` terms can gain `n/2` over the unrounded sum. `IndexIVFRaBitQFastScan` also folds its per-probe bias into the bound, because that bias is rounded into the same accumulator.

`IndexPQFastScan` only reaches the bound when a sub-vector holds one dimension. A nearest centroid keeps the selected entries near the bottom of each column. `IndexSQFastScan` sets `M = d`, so it fails above about `d = 512`. At `d = 1024` it goes from R@1 0.00 to 1.00.

Search speed does not change. The scale is computed once per query, and the inner loop is untouched.

An index at `M <= 256` quantizes to the same bytes as before, because the sum term does not bind there.

Reviewed By: junjieqi

Differential Revision: D120638521

fbshipit-source-id: 27d5dd15f5a60a9c80cec1f63f53ac9c6c51b8ff
2026-09-25 13:47:19 -07:00

809 lines
25 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.
import unittest
import time
import numpy as np
import faiss
from faiss.contrib import datasets
from common_faiss_tests import (
compare_binary_result_lists,
for_all_simd_levels,
NoneSIMDLevel,
)
# the tests tend to timeout in stress modes + dev otherwise
faiss.omp_set_num_threads(4)
@for_all_simd_levels
class TestSearch(unittest.TestCase):
def test_PQ4_accuracy(self):
ds = datasets.SyntheticDataset(32, 2000, 5000, 1000)
index_gt = faiss.IndexFlatL2(32)
index_gt.add(ds.get_database())
Dref, Iref = index_gt.search(ds.get_queries(), 10)
index = faiss.index_factory(32, "PQ16x4fs")
index.train(ds.get_train())
index.add(ds.get_database())
Da, Ia = index.search(ds.get_queries(), 10)
nq = Iref.shape[0]
recall_at_1 = (Iref[:, 0] == Ia[:, 0]).sum() / nq
assert recall_at_1 > 0.6
def test_PQ4_search_matches_none(self):
"""Fast-scan PQ search dispatches via the 256/512-bit QBS path.
The integer QBS kernel is deterministic across SIMD levels *only if*
the upstream float PQ distance table is bit-identical AND the
handler's end() method (int-to-float conversion) compiles to
identical FP code. Two cases break this:
1. aarch64 NEON/SVE: float distance-table computation reduces
in a different order, producing non-bit-identical LUT.
2. DD mode: per-SIMD TUs compile with different flags (-mfma
vs no -mfma), so handler end() may contract mul+add into
fma, producing 1-ULP float distance differences.
In both cases, fall back to a recall@1 check.
"""
ds = datasets.SyntheticDataset(32, 2000, 5000, 200)
index = faiss.index_factory(32, "PQ16x4fs")
index.train(ds.get_train())
index.add(ds.get_database())
xq = ds.get_queries()
nq = xq.shape[0]
M, ksub = index.pq.M, index.pq.ksub
tab = np.zeros((nq, M, ksub), dtype="float32")
index.pq.compute_distance_tables(
nq, faiss.swig_ptr(xq), faiss.swig_ptr(tab)
)
D, I = index.search(xq, 10)
with NoneSIMDLevel():
tab_none = np.zeros((nq, M, ksub), dtype="float32")
index.pq.compute_distance_tables(
nq, faiss.swig_ptr(xq), faiss.swig_ptr(tab_none)
)
D_none, I_none = index.search(xq, 10)
lut_diffs = int((tab != tab_none).sum())
dd_mode = "DD" in faiss.get_compile_options()
if lut_diffs == 0 and not dd_mode:
compare_binary_result_lists(D, I, D_none, I_none)
else:
recall_at_1 = (I[:, 0] == I_none[:, 0]).mean()
self.assertGreater(
recall_at_1,
0.95,
f"LUT diverges ({lut_diffs} entries differ, DD={dd_mode}); "
f"recall@1 vs NONE = {recall_at_1:.3f}",
)
class TestFastScanDDSpeed(unittest.TestCase):
"""Verify DD-mode FastScan kernels use real SIMD."""
def _build_index(self):
d, n, nq, k = 128, 100_000, 1000, 10
np.random.seed(123)
xb = np.random.randn(n, d).astype("float32")
xq = np.random.randn(nq, d).astype("float32")
index = faiss.index_factory(d, "PQ16x4fs")
index.train(xb)
index.add(xb)
index.search(xq, k)
return index, xq, k
def _bench(self, index, xq, k, level, iters=50):
faiss.SIMDConfig.set_level(level)
t0 = time.time()
for _ in range(iters):
index.search(xq, k)
return time.time() - t0
def _check_speedup(self, none_time, simd_time, label):
speedup = none_time / simd_time
print(
f"FastScan DD: NONE={none_time:.3f}s, "
f"{label}={simd_time:.3f}s, {speedup:.1f}x"
)
# 2x is conservative: scalar-to-AVX2 theoretical max is ~32x,
# observed 5-27x in isolation. 2x leaves margin for CI noise.
self.assertGreater(
speedup,
2.0,
f"{label} should be >2x faster than NONE, " f"got {speedup:.1f}x",
)
@unittest.skipUnless(
"DD" in faiss.get_compile_options()
and "OPTIMIZE" in faiss.get_compile_options()
and faiss.SIMDConfig.is_simd_level_available(faiss.SIMDLevel_AVX2),
"DD-only, needs opt mode and AVX2",
)
def test_dd_fastscan_avx2_faster_than_none(self):
index, xq, k = self._build_index()
none_t = self._bench(index, xq, k, faiss.SIMDLevel_NONE)
avx2_t = self._bench(index, xq, k, faiss.SIMDLevel_AVX2)
faiss.SIMDConfig.set_level(faiss.SIMDConfig.get_dispatched_level())
self._check_speedup(none_t, avx2_t, "AVX2")
@unittest.skipUnless(
"DD" in faiss.get_compile_options()
and "OPTIMIZE" in faiss.get_compile_options()
and faiss.SIMDConfig.is_simd_level_available(faiss.SIMDLevel_AVX512),
"DD-only, needs opt mode and AVX512",
)
def test_dd_fastscan_avx512_faster_than_none(self):
index, xq, k = self._build_index()
none_t = self._bench(index, xq, k, faiss.SIMDLevel_NONE)
avx512_t = self._bench(index, xq, k, faiss.SIMDLevel_AVX512)
faiss.SIMDConfig.set_level(faiss.SIMDConfig.get_dispatched_level())
self._check_speedup(none_t, avx512_t, "AVX512")
@for_all_simd_levels
class TestRounding(unittest.TestCase):
def do_test_rounding(self, implem=4, metric=faiss.METRIC_L2):
ds = datasets.SyntheticDataset(32, 2000, 5000, 200)
index = faiss.index_factory(32, "PQ16x4", metric)
index.train(ds.get_train())
index.add(ds.get_database())
Dref, Iref = index.search(ds.get_queries(), 10)
nq = Iref.shape[0]
index2 = faiss.IndexPQFastScan(index)
# simply repro normal search
index2.implem = 2
D2, I2 = index2.search(ds.get_queries(), 10)
np.testing.assert_array_equal(I2, Iref)
np.testing.assert_array_equal(D2, Dref)
# rounded LUT with correction
index2.implem = implem
D4, I4 = index2.search(ds.get_queries(), 10)
# check accuracy of indexes
recalls = {}
for rank in 1, 10:
recalls[rank] = (Iref[:, :1] == I4[:, :rank]).sum() / nq
min_r1 = 0.98 if metric == faiss.METRIC_INNER_PRODUCT else 0.99
self.assertGreaterEqual(recalls[1], min_r1)
self.assertGreater(recalls[10], 0.995)
# check accuracy of distances
# err3 = ((D3 - D2) ** 2).sum()
err4 = ((D4 - D2) ** 2).sum()
nf = (D2**2).sum()
self.assertLess(err4, nf * 1e-4)
def test_implem_4(self):
self.do_test_rounding(4)
def test_implem_4_ip(self):
self.do_test_rounding(4, faiss.METRIC_INNER_PRODUCT)
def test_implem_12(self):
self.do_test_rounding(12)
def test_implem_12_ip(self):
self.do_test_rounding(12, faiss.METRIC_INNER_PRODUCT)
def test_implem_14(self):
self.do_test_rounding(14)
def test_implem_14_ip(self):
self.do_test_rounding(12, faiss.METRIC_INNER_PRODUCT)
class TestManyPQSubQuantizers(unittest.TestCase):
def do_test_recall_matches_pq(self, d):
ds = datasets.SyntheticDataset(d, 2000, 5000, 50)
# M = d gives one dimension per sub-quantizer.
pq = faiss.IndexPQ(d, d, 4)
pq.train(ds.get_train())
pq.add(ds.get_database())
fs = faiss.IndexPQFastScan(d, d, 4)
fs.train(ds.get_train())
fs.add(ds.get_database())
Dref, Iref = pq.search(ds.get_queries(), 10)
D, I = fs.search(ds.get_queries(), 10)
agree = (Iref[:, :1] == I[:, :1]).sum() / Iref.shape[0]
self.assertGreater(agree, 0.9)
def test_m_1024(self):
self.do_test_recall_matches_pq(1024)
@for_all_simd_levels
class TestReconstruct(unittest.TestCase):
def test_pqfastscan(self):
ds = datasets.SyntheticDataset(20, 1000, 1000, 0)
index = faiss.index_factory(20, "PQ5x4")
index.train(ds.get_train())
index.add(ds.get_database())
recons = index.reconstruct_n(0, index.ntotal)
index2 = faiss.IndexPQFastScan(index)
recons2 = index2.reconstruct_n(0, index.ntotal)
np.testing.assert_array_equal(recons, recons2)
def test_aqfastscan(self):
ds = datasets.SyntheticDataset(20, 1000, 1000, 0)
index = faiss.index_factory(20, "RQ5x4_Nrq2x4")
index.train(ds.get_train())
index.add(ds.get_database())
recons = index.reconstruct_n(0, index.ntotal)
index2 = faiss.IndexAdditiveQuantizerFastScan(index)
recons2 = index2.reconstruct_n(0, index.ntotal)
np.testing.assert_array_equal(recons, recons2)
#########################################################
# Kernel unit test
#########################################################
def reference_accu(codes, LUT):
nq, nsp, is_16 = LUT.shape
nb, nsp_2 = codes.shape
assert is_16 == 16
assert nsp_2 == nsp // 2
accu = np.zeros((nq, nb), "uint16")
for i in range(nq):
for j in range(nb):
a = np.uint16(0)
for sp in range(0, nsp, 2):
c = codes[j, sp // 2]
a += LUT[i, sp, c & 15].astype("uint16")
a += LUT[i, sp + 1, c >> 4].astype("uint16")
accu[i, j] = a
return accu
# disabled because the function to write to mem is not implemented currently
class ThisIsNotATestLoop5: # (unittest.TestCase):
def do_loop5_kernel(self, nq, bb):
"""unit test for the accumulation kernel"""
nb = bb * 32 # databse size
nsp = 24 # number of sub-quantizers
rs = np.random.RandomState(123)
codes = rs.randint(256, size=(nb, nsp // 2)).astype("uint8")
LUT = rs.randint(256, size=(nq, nsp, 16)).astype("uint8")
accu_ref = reference_accu(codes, LUT)
def to_A(x):
return faiss.array_to_AlignedTable(x.ravel())
sp = faiss.swig_ptr
LUT_a = faiss.AlignedTableUint8(LUT.size)
faiss.pq4_pack_LUT(nq, nsp, sp(LUT), LUT_a.get())
codes_a = faiss.AlignedTableUint8(codes.size)
faiss.pq4_pack_codes(sp(codes), nb, nsp, nb, nb, nsp, codes_a.get())
accu_a = faiss.AlignedTableUint16(nq * nb)
accu_a.clear()
faiss.loop5_kernel_accumulate_1_block_to_mem(
nq, nb, nsp, codes_a.get(), LUT_a.get(), accu_a.get()
)
accu = faiss.AlignedTable_to_array(accu_a).reshape(nq, nb)
np.testing.assert_array_equal(accu_ref, accu)
def test_11(self):
self.do_loop5_kernel(1, 1)
def test_21(self):
self.do_loop5_kernel(2, 1)
def test_12(self):
self.do_loop5_kernel(1, 2)
def test_22(self):
self.do_loop5_kernel(2, 2)
##########################################################
# Tests for various IndexPQFastScan implementations
##########################################################
def verify_with_draws(testcase, Dref, Iref, Dnew, Inew):
"""Verify a list of results where there are draws in the distances
(because they are integer)."""
np.testing.assert_array_almost_equal(Dref, Dnew, decimal=5)
# here we have to be careful because of draws
for i in range(len(Iref)):
if np.all(Iref[i] == Inew[i]):
continue
# we can deduce nothing about the latest line
skip_dis = Dref[i, -1]
for dis in np.unique(Dref):
if dis == skip_dis:
continue
mask = Dref[i, :] == dis
testcase.assertEqual(set(Iref[i, mask]), set(Inew[i, mask]))
class TestImplems(unittest.TestCase):
def __init__(self, *args):
unittest.TestCase.__init__(self, *args)
self.cache = {}
self.k = 10
def get_index(self, d, metric):
if (d, metric) not in self.cache:
ds = datasets.SyntheticDataset(d, 1000, 2000, 200)
target_size = d // 2
index = faiss.index_factory(d, "PQ%dx4" % target_size, metric)
index.train(ds.get_train())
index.add(ds.get_database())
index2 = faiss.IndexPQFastScan(index)
# uint8 LUT but no SIMD
index2.implem = 4
Dref, Iref = index2.search(ds.get_queries(), 10)
# check CodePacker
codes_ref = faiss.vector_to_array(index.codes)
codes_ref = codes_ref.reshape(-1, index.code_size)
index2codes = faiss.vector_to_array(index2.codes)
code_packer = index2.get_CodePacker()
index2codes = index2codes.reshape(-1, code_packer.block_size)
for i in range(0, len(codes_ref), 13):
code_new = code_packer.unpack_1(index2codes, i)
np.testing.assert_array_equal(codes_ref[i], code_new)
self.cache[(d, metric)] = (ds, index, Dref, Iref)
return self.cache[(d, metric)]
def do_with_params(self, d, params, metric=faiss.METRIC_L2):
ds, index, Dref, Iref = self.get_index(d, metric)
index2 = self.build_fast_scan_index(index, params)
Dnew, Inew = index2.search(ds.get_queries(), self.k)
Dref = Dref[:, : self.k]
Iref = Iref[:, : self.k]
verify_with_draws(self, Dref, Iref, Dnew, Inew)
def build_fast_scan_index(self, index, params):
index2 = faiss.IndexPQFastScan(index)
index2.implem = 5
return index2
@for_all_simd_levels
class TestImplem12(TestImplems):
def build_fast_scan_index(self, index, qbs):
index2 = faiss.IndexPQFastScan(index)
index2.qbs = qbs
index2.implem = 12
return index2
def test_qbs7(self):
self.do_with_params(32, 0x223)
def test_qbs7b(self):
self.do_with_params(32, 0x133)
def test_qbs6(self):
self.do_with_params(32, 0x33)
def test_qbs6_ip(self):
self.do_with_params(32, 0x33, faiss.METRIC_INNER_PRODUCT)
def test_qbs6b(self):
# test codepath where qbs is not known at compile time
self.do_with_params(32, 0x1113)
def test_qbs6_odd_dim(self):
self.do_with_params(30, 0x33)
@for_all_simd_levels
class TestImplem13(TestImplems):
def build_fast_scan_index(self, index, qbs):
index2 = faiss.IndexPQFastScan(index)
index2.qbs = qbs
index2.implem = 13
return index2
def test_qbs7(self):
self.do_with_params(32, 0x223)
def test_qbs7_k1(self):
self.k = 1
self.do_with_params(32, 0x223)
@for_all_simd_levels
class TestImplem14(TestImplems):
def build_fast_scan_index(self, index, params):
qbs, bbs = params
index2 = faiss.IndexPQFastScan(index, bbs)
index2.qbs = qbs
index2.implem = 14
return index2
def test_1_32(self):
self.do_with_params(32, (1, 32))
def test_1_64(self):
self.do_with_params(32, (1, 64))
def test_2_32(self):
self.do_with_params(32, (2, 32))
def test_2_64(self):
self.do_with_params(32, (2, 64))
def test_qbs_1_32_k1(self):
self.k = 1
self.do_with_params(32, (1, 32))
def test_qbs_1_64_k1(self):
self.k = 1
self.do_with_params(32, (1, 64))
def test_1_32_odd_dim(self):
self.do_with_params(30, (1, 32))
def test_1_64_odd_dim(self):
self.do_with_params(30, (1, 64))
@for_all_simd_levels
class TestImplem15(TestImplems):
def build_fast_scan_index(self, index, params):
qbs, bbs = params
index2 = faiss.IndexPQFastScan(index, bbs)
index2.qbs = qbs
index2.implem = 15
return index2
def test_1_32(self):
self.do_with_params(32, (1, 32))
def test_2_64(self):
self.do_with_params(32, (2, 64))
@for_all_simd_levels
class TestAdd(unittest.TestCase):
def do_test_add(self, d, bbs):
ds = datasets.SyntheticDataset(d, 2000, 5000, 200)
index = faiss.index_factory(d, f"PQ{d // 2}x4np")
index.train(ds.get_train())
xb = ds.get_database()
index.add(xb[:1235])
index2 = faiss.IndexPQFastScan(index, bbs)
index2.add(xb[1235:])
new_codes = faiss.AlignedTable_to_array(index2.codes)
index.add(xb[1235:])
index3 = faiss.IndexPQFastScan(index, bbs)
ref_codes = faiss.AlignedTable_to_array(index3.codes)
self.assertEqual(index3.ntotal, index2.ntotal)
np.testing.assert_array_equal(ref_codes, new_codes)
def test_add(self):
self.do_test_add(32, 32)
def test_add_bbs64(self):
self.do_test_add(32, 64)
def test_add_odd_d(self):
self.do_test_add(30, 64)
def test_constructor(self):
d = 32
ds = datasets.SyntheticDataset(d, 2000, 5000, 200)
index = faiss.index_factory(d, f"PQ{d // 2}x4np")
index.train(ds.get_train())
index.add(ds.get_database())
Dref, Iref = index.search(ds.get_queries(), 10)
nq = Iref.shape[0]
index2 = faiss.IndexPQFastScan(d, d // 2, 4)
index2.train(ds.get_train())
index2.add(ds.get_database())
Dnew, Inew = index2.search(ds.get_queries(), 10)
recall_at_1 = (Iref[:, 0] == Inew[:, 0]).sum() / nq
self.assertGreaterEqual(recall_at_1, 0.99)
data = faiss.serialize_index(index2)
index3 = faiss.deserialize_index(data)
self.assertEqual(index2.implem, index3.implem)
D3, I3 = index3.search(ds.get_queries(), 10)
np.testing.assert_array_equal(D3, Dnew)
np.testing.assert_array_equal(I3, Inew)
class TestAQFastScan(unittest.TestCase):
def subtest_accuracy(self, aq, st, implem, metric_type="L2"):
"""
Compare IndexAdditiveQuantizerFastScan with IndexAQ (qint8)
"""
d = 16
ds = datasets.SyntheticDataset(d, 1000, 1000, 500, metric_type)
gt = ds.get_groundtruth(k=1)
if metric_type == "L2":
metric = faiss.METRIC_L2
postfix1 = "_Nqint8"
postfix2 = f"_N{st}2x4"
else:
metric = faiss.METRIC_INNER_PRODUCT
postfix1 = postfix2 = ""
index = faiss.index_factory(d, f"{aq}3x4{postfix1}", metric)
index.train(ds.get_train())
index.add(ds.get_database())
Dref, Iref = index.search(ds.get_queries(), 1)
indexfs = faiss.index_factory(d, f"{aq}3x4fs_32{postfix2}", metric)
indexfs.train(ds.get_train())
indexfs.add(ds.get_database())
indexfs.implem = implem
Da, Ia = indexfs.search(ds.get_queries(), 1)
nq = Iref.shape[0]
recall_ref = (Iref == gt).sum() / nq
recall = (Ia == gt).sum() / nq
assert abs(recall_ref - recall) < 0.05
def xx_test_accuracy(self):
for metric in "L2", "IP":
for implem in 0, 12, 13, 14, 15:
self.subtest_accuracy("RQ", "rq", implem, metric)
self.subtest_accuracy("LSQ", "lsq", implem, metric)
def subtest_from_idxaq(self, implem, metric):
if metric == "L2":
metric_type = faiss.METRIC_L2
st = "_Nrq2x4"
else:
metric_type = faiss.METRIC_INNER_PRODUCT
st = ""
d = 16
ds = datasets.SyntheticDataset(d, 1000, 2000, 1000, metric=metric)
gt = ds.get_groundtruth(k=1)
index = faiss.index_factory(d, "RQ8x4" + st, metric_type)
index.train(ds.get_train())
index.add(ds.get_database())
Dref, Iref = index.search(ds.get_queries(), 1)
indexfs = faiss.IndexAdditiveQuantizerFastScan(index)
indexfs.implem = implem
D1, I1 = indexfs.search(ds.get_queries(), 1)
nq = Iref.shape[0]
recall_ref = (Iref == gt).sum() / nq
recall1 = (I1 == gt).sum() / nq
assert abs(recall_ref - recall1) < 0.05
def xx_test_from_idxaq(self):
for implem in 2, 3, 4:
self.subtest_from_idxaq(implem, "L2")
self.subtest_from_idxaq(implem, "IP")
def subtest_factory(self, aq, M, bbs, st):
"""
Format: {AQ}{M}x4fs_{bbs}_N{st}
AQ (str): `LSQ` or `RQ`
M (int): number of subquantizers
bbs (int): build block size
st (str): search type, `lsq2x4` or `rq2x4`
"""
AQ = faiss.AdditiveQuantizer
d = 16
if bbs > 0:
index = faiss.index_factory(d, f"{aq}{M}x4fs_{bbs}_N{st}2x4")
else:
index = faiss.index_factory(d, f"{aq}{M}x4fs_N{st}2x4")
bbs = 32
assert index.bbs == bbs
aq = faiss.downcast_AdditiveQuantizer(index.aq)
assert aq.M == M
if aq == "LSQ":
assert isinstance(aq, faiss.LocalSearchQuantizer)
if aq == "RQ":
assert isinstance(aq, faiss.ResidualQuantizer)
if st == "lsq":
assert aq.search_type == AQ.ST_norm_lsq2x4
if st == "rq":
assert aq.search_type == AQ.ST_norm_rq2x4
def test_factory(self):
self.subtest_factory("LSQ", 16, 64, "lsq")
self.subtest_factory("LSQ", 16, 64, "rq")
self.subtest_factory("RQ", 16, 64, "rq")
self.subtest_factory("RQ", 16, 64, "lsq")
self.subtest_factory("LSQ", 64, 0, "lsq")
def subtest_io(self, factory_str):
d = 8
ds = datasets.SyntheticDataset(d, 1000, 500, 100)
index = faiss.index_factory(d, factory_str)
index.train(ds.get_train())
index.add(ds.get_database())
D1, I1 = index.search(ds.get_queries(), 1)
index2 = faiss.deserialize_index(faiss.serialize_index(index))
D2, I2 = index2.search(ds.get_queries(), 1)
np.testing.assert_array_equal(I1, I2)
def test_io(self):
self.subtest_io("LSQ4x4fs_Nlsq2x4")
self.subtest_io("LSQ4x4fs_Nrq2x4")
self.subtest_io("RQ4x4fs_Nrq2x4")
self.subtest_io("RQ4x4fs_Nlsq2x4")
# programatically generate tests to get finer test granularity.
def add_TestAQFastScan_subset_accuracy(aq, st, implem, metric):
setattr(
TestAQFastScan,
f"test_accuracy_{metric}_{aq}_implem{implem}",
lambda self: self.subtest_accuracy(aq, st, implem, metric),
)
for metric in "L2", "IP":
for implem in 0, 12, 13, 14, 15:
add_TestAQFastScan_subset_accuracy("LSQ", "lsq", implem, metric)
add_TestAQFastScan_subset_accuracy("RQ", "rq", implem, metric)
def add_TestAQFastScan_subtest_from_idxaq(implem, metric):
setattr(
TestAQFastScan,
f"test_from_idxaq_{metric}_implem{implem}",
lambda self: self.subtest_from_idxaq(implem, metric),
)
for implem in 2, 3, 4:
add_TestAQFastScan_subtest_from_idxaq(implem, "L2")
add_TestAQFastScan_subtest_from_idxaq(implem, "IP")
# Apply decorator after dynamic method generation.
TestAQFastScan = for_all_simd_levels(TestAQFastScan)
@for_all_simd_levels
class TestPAQFastScan(unittest.TestCase):
def subtest_accuracy(self, paq):
"""
Compare IndexPAQFastScan with IndexPAQ (qint8)
"""
d = 16
ds = datasets.SyntheticDataset(d, 1000, 1000, 500)
gt = ds.get_groundtruth(k=1)
index = faiss.index_factory(d, f"{paq}2x3x4_Nqint8")
index.train(ds.get_train())
index.add(ds.get_database())
Dref, Iref = index.search(ds.get_queries(), 1)
indexfs = faiss.index_factory(d, f"{paq}2x3x4fs_Nlsq2x4")
indexfs.train(ds.get_train())
indexfs.add(ds.get_database())
Da, Ia = indexfs.search(ds.get_queries(), 1)
nq = Iref.shape[0]
recall_ref = (Iref == gt).sum() / nq
recall = (Ia == gt).sum() / nq
assert abs(recall_ref - recall) < 0.05
def test_accuracy_PLSQ(self):
self.subtest_accuracy("PLSQ")
def test_accuracy_PRQ(self):
self.subtest_accuracy("PRQ")
def subtest_factory(self, paq):
index = faiss.index_factory(16, f"{paq}2x3x4fs_Nlsq2x4")
q = faiss.downcast_Quantizer(index.aq)
self.assertEqual(q.nsplits, 2)
self.assertEqual(q.subquantizer(0).M, 3)
def test_factory(self):
self.subtest_factory("PRQ")
self.subtest_factory("PLSQ")
def subtest_io(self, factory_str):
d = 8
ds = datasets.SyntheticDataset(d, 1000, 500, 100)
index = faiss.index_factory(d, factory_str)
index.train(ds.get_train())
index.add(ds.get_database())
D1, I1 = index.search(ds.get_queries(), 1)
index2 = faiss.deserialize_index(faiss.serialize_index(index))
D2, I2 = index2.search(ds.get_queries(), 1)
np.testing.assert_array_equal(I1, I2)
def test_io(self):
self.subtest_io("PLSQ2x3x4fs_Nlsq2x4")
self.subtest_io("PRQ2x3x4fs_Nrq2x4")
@for_all_simd_levels
class TestBlockDecode(unittest.TestCase):
def test_issue_2739(self):
ds = datasets.SyntheticDataset(960, 200, 1, 0)
M = 32
index = faiss.index_factory(ds.d, f"PQ{M}x4fs")
index.train(ds.get_train())
index.add(ds.get_database())
decoded = index.pq.decode(index.pq.compute_codes(ds.get_database()))[
0, ::100
]
np.testing.assert_array_equal(decoded, index.reconstruct(0)[::100])