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# 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 numpy as np
d = 64 # dimension
nb = 100000 # database size
nq = 10000 # nb of queries
np.random.seed(1234) # make reproducible
xb = np.random.random((nb, d)).astype('float32')
xb[:, 0] += np.arange(nb) / 1000.
xq = np.random.random((nq, d)).astype('float32')
xq[:, 0] += np.arange(nq) / 1000.
import faiss # make faiss available
index = faiss.IndexFlatL2(d) # build the index
print(index.is_trained)
index.add(xb) # add vectors to the index
print(index.ntotal)
k = 4 # we want to see 4 nearest neighbors
D, I = index.search(xb[:5], k) # sanity check
print(I)
print(D)
D, I = index.search(xq, k) # actual search
print(I[:5]) # neighbors of the 5 first queries
print(I[-5:]) # neighbors of the 5 last queries

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# 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 numpy as np
d = 64 # dimension
nb = 100000 # database size
nq = 10000 # nb of queries
np.random.seed(1234) # make reproducible
xb = np.random.random((nb, d)).astype('float32')
xb[:, 0] += np.arange(nb) / 1000.
xq = np.random.random((nq, d)).astype('float32')
xq[:, 0] += np.arange(nq) / 1000.
import faiss
nlist = 100
k = 4
quantizer = faiss.IndexFlatL2(d) # the other index
index = faiss.IndexIVFFlat(quantizer, d, nlist, faiss.METRIC_L2)
# here we specify METRIC_L2, by default it performs inner-product search
assert not index.is_trained
index.train(xb)
assert index.is_trained
index.add(xb) # add may be a bit slower as well
D, I = index.search(xq, k) # actual search
print(I[-5:]) # neighbors of the 5 last queries
index.nprobe = 10 # default nprobe is 1, try a few more
D, I = index.search(xq, k)
print(I[-5:]) # neighbors of the 5 last queries

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# 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 numpy as np
d = 64 # dimension
nb = 100000 # database size
nq = 10000 # nb of queries
np.random.seed(1234) # make reproducible
xb = np.random.random((nb, d)).astype('float32')
xb[:, 0] += np.arange(nb) / 1000.
xq = np.random.random((nq, d)).astype('float32')
xq[:, 0] += np.arange(nq) / 1000.
import faiss
nlist = 100
m = 8
k = 4
quantizer = faiss.IndexFlatL2(d) # this remains the same
index = faiss.IndexIVFPQ(quantizer, d, nlist, m, 8)
# 8 specifies that each sub-vector is encoded as 8 bits
index.train(xb)
index.add(xb)
D, I = index.search(xb[:5], k) # sanity check
print(I)
print(D)
index.nprobe = 10 # make comparable with experiment above
D, I = index.search(xq, k) # search
print(I[-5:])

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# 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 numpy as np
d = 64 # dimension
nb = 100000 # database size
nq = 10000 # nb of queries
np.random.seed(1234) # make reproducible
xb = np.random.random((nb, d)).astype('float32')
xb[:, 0] += np.arange(nb) / 1000.
xq = np.random.random((nq, d)).astype('float32')
xq[:, 0] += np.arange(nq) / 1000.
import faiss # make faiss available
res = faiss.StandardGpuResources() # use a single GPU
## Using a flat index
index_flat = faiss.IndexFlatL2(d) # build a flat (CPU) index
# make it a flat GPU index
gpu_index_flat = faiss.index_cpu_to_gpu(res, 0, index_flat)
gpu_index_flat.add(xb) # add vectors to the index
print(gpu_index_flat.ntotal)
k = 4 # we want to see 4 nearest neighbors
D, I = gpu_index_flat.search(xq, k) # actual search
print(I[:5]) # neighbors of the 5 first queries
print(I[-5:]) # neighbors of the 5 last queries
## Using an IVF index
nlist = 100
quantizer = faiss.IndexFlatL2(d) # the other index
index_ivf = faiss.IndexIVFFlat(quantizer, d, nlist, faiss.METRIC_L2)
# here we specify METRIC_L2, by default it performs inner-product search
# make it an IVF GPU index
gpu_index_ivf = faiss.index_cpu_to_gpu(res, 0, index_ivf)
assert not gpu_index_ivf.is_trained
gpu_index_ivf.train(xb) # add vectors to the index
assert gpu_index_ivf.is_trained
gpu_index_ivf.add(xb) # add vectors to the index
print(gpu_index_ivf.ntotal)
k = 4 # we want to see 4 nearest neighbors
D, I = gpu_index_ivf.search(xq, k) # actual search
print(I[:5]) # neighbors of the 5 first queries
print(I[-5:]) # neighbors of the 5 last queries

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# 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 numpy as np
d = 64 # dimension
nb = 100000 # database size
nq = 10000 # nb of queries
np.random.seed(1234) # make reproducible
xb = np.random.random((nb, d)).astype('float32')
xb[:, 0] += np.arange(nb) / 1000.
xq = np.random.random((nq, d)).astype('float32')
xq[:, 0] += np.arange(nq) / 1000.
import faiss # make faiss available
ngpus = faiss.get_num_gpus()
print("number of GPUs:", ngpus)
cpu_index = faiss.IndexFlatL2(d)
gpu_index = faiss.index_cpu_to_all_gpus( # build the index
cpu_index
)
gpu_index.add(xb) # add vectors to the index
print(gpu_index.ntotal)
k = 4 # we want to see 4 nearest neighbors
D, I = gpu_index.search(xq, k) # actual search
print(I[:5]) # neighbors of the 5 first queries
print(I[-5:]) # neighbors of the 5 last queries

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# 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 faiss
import numpy as np
d = 64 # dimension
nb = 100000 # database size
nq = 10000 # nb of queries
np.random.seed(1234) # make reproducible
xb = np.random.random((nb, d)).astype('float32') # 64-dim *nb queries
xb[:, 0] += np.arange(nb) / 1000.
xq = np.random.random((nq, d)).astype('float32')
xq[:, 0] += np.arange(nq) / 1000.
m = 8 # 8 specifies that the number of sub-vector is 8
k = 4 # number of dimension in etracted vector
n_bit = 4 # 4 specifies that each sub-vector is encoded as 4 bits
bbs = 32 # build block size ( bbs % 32 == 0 ) for PQ
index = faiss.IndexPQFastScan(d, m, n_bit, faiss.METRIC_L2, bbs)
# construct FastScan Index
assert not index.is_trained
index.train(xb) # Train vectors data index within mockup database
assert index.is_trained
index.add(xb)
D, I = index.search(xb[:5], k) # sanity check
print(I)
print(D)
index.nprobe = 10 # make comparable with experiment above
D, I = index.search(xq, k) # search
print(I[-5:]) # neighbors of the 5 last queries

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# 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 faiss
import numpy as np
d = 64 # dimension
nb = 100000 # database size
nq = 10000 # nb of queries
np.random.seed(1234) # make reproducible
xb = np.random.random((nb, d)).astype('float32') # 64-dim *nb queries
xb[:, 0] += np.arange(nb) / 1000.
xq = np.random.random((nq, d)).astype('float32')
xq[:, 0] += np.arange(nq) / 1000.
m = 8 # 8 specifies that the number of sub-vector is 8
k = 4 # number of dimension in etracted vector
n_bit = 4 # 4 specifies that each sub-vector is encoded as 4 bits
bbs = 32 # build block size ( bbs % 32 == 0 ) for PQ
index = faiss.IndexPQFastScan(d, m, n_bit, faiss.METRIC_L2)
index_refine = faiss.IndexRefineFlat(index)
# construct FastScan and run index refinement
assert not index_refine.is_trained
index_refine.train(xb) # Train vectors data index within mockup database
assert index_refine.is_trained
index_refine.add(xb)
params = faiss.IndexRefineSearchParameters(k_factor=3)
D, I = index_refine.search(xq[:5], 10, params=params)
print(I)
print(D)
index.nprobe = 10 # make comparable with experiment above
D, I = index.search(xq[:5], k) # search
print(I[-5:])

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# 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 faiss
from faiss.contrib.evaluation import knn_intersection_measure
from faiss.contrib import datasets
# 64-dim vectors, 50000 vectors in the training, 100000 in database,
# 10000 in queries, dtype ('float32')
ds = datasets.SyntheticDataset(64, 50000, 100000, 10000)
d = 64 # dimension
# Constructing the refine PQ index with SQfp16 with index factory
index_fp16 = faiss.index_factory(d, 'PQ32x4fs,Refine(SQfp16)')
index_fp16.train(ds.get_train())
index_fp16.add(ds.get_database())
# Constructing the refine PQ index with SQ8
index_sq8 = faiss.index_factory(d, 'PQ32x4fs,Refine(SQ8)')
index_sq8.train(ds.get_train())
index_sq8.add(ds.get_database())
# Parameterization on k factor while doing search for index refinement
k_factor = 3.0
params = faiss.IndexRefineSearchParameters(k_factor=k_factor)
# Perform index search using different index refinement
D_fp16, I_fp16 = index_fp16.search(ds.get_queries(), 100, params=params)
D_sq8, I_sq8 = index_sq8.search(ds.get_queries(), 100, params=params)
# Calculating knn intersection measure for different index types on refinement
KIM_fp16 = knn_intersection_measure(I_fp16, ds.get_groundtruth())
KIM_sq8 = knn_intersection_measure(I_sq8, ds.get_groundtruth())
# KNN intersection measure accuracy shows that choosing SQ8 impacts accuracy
assert (KIM_fp16 > KIM_sq8)
print(I_sq8[:5])
print(I_fp16[:5])