File ScalarQuantizer.h
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namespace faiss
Copyright (c) Facebook, Inc. and its affiliates.
This source code is licensed under the MIT license found in the LICENSE file in the root directory of this source tree.
Copyright (c) Facebook, Inc. and its affiliates.
This source code is licensed under the MIT license found in the LICENSE file in the root directory of this source tree. Implementation of k-means clustering with many variants.
Copyright (c) Facebook, Inc. and its affiliates.
This source code is licensed under the MIT license found in the LICENSE file in the root directory of this source tree. IDSelector is intended to define a subset of vectors to handle (for removal or as subset to search)
Copyright (c) Facebook, Inc. and its affiliates.
This source code is licensed under the MIT license found in the LICENSE file in the root directory of this source tree. PQ4 SIMD packing and accumulation functions
The basic kernel accumulates nq query vectors with bbs = nb * 2 * 16 vectors and produces an output matrix for that. It is interesting for nq * nb <= 4, otherwise register spilling becomes too large.
The implementation of these functions is spread over 3 cpp files to reduce parallel compile times. Templates are instantiated explicitly.
Copyright (c) Facebook, Inc. and its affiliates.
This source code is licensed under the MIT license found in the LICENSE file in the root directory of this source tree. This file contains callbacks for kernels that compute distances.
Throughout the library, vectors are provided as float * pointers. Most algorithms can be optimized when several vectors are processed (added/searched) together in a batch. In this case, they are passed in as a matrix. When n vectors of size d are provided as float * x, component j of vector i is
x[ i * d + j ]
where 0 <= i < n and 0 <= j < d. In other words, matrices are always compact. When specifying the size of the matrix, we call it an n*d matrix, which implies a row-major storage.
Copyright (c) Facebook, Inc. and its affiliates.
This source code is licensed under the MIT license found in the LICENSE file in the root directory of this source tree. I/O functions can read/write to a filename, a file handle or to an object that abstracts the medium.
The read functions return objects that should be deallocated with delete. All references within these objectes are owned by the object.
Copyright (c) Facebook, Inc. and its affiliates.
This source code is licensed under the MIT license found in the LICENSE file in the root directory of this source tree. Definition of inverted lists + a few common classes that implement the interface.
Copyright (c) Facebook, Inc. and its affiliates.
This source code is licensed under the MIT license found in the LICENSE file in the root directory of this source tree. Since IVF (inverted file) indexes are of so much use for large-scale use cases, we group a few functions related to them in this small library. Most functions work both on IndexIVFs and IndexIVFs embedded within an IndexPreTransform.
Copyright (c) Facebook, Inc. and its affiliates.
This source code is licensed under the MIT license found in the LICENSE file in the root directory of this source tree. In this file are the implementations of extra metrics beyond L2 and inner product
Copyright (c) Facebook, Inc. and its affiliates.
This source code is licensed under the MIT license found in the LICENSE file in the root directory of this source tree. Defines a few objects that apply transformations to a set of vectors Often these are pre-processing steps.
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struct ScalarQuantizer : public faiss::Quantizer
- #include <ScalarQuantizer.h>
The uniform quantizer has a range [vmin, vmax]. The range can be the same for all dimensions (uniform) or specific per dimension (default).
Public Types
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enum QuantizerType
Values:
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enumerator QT_8bit
8 bits per component
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enumerator QT_4bit
4 bits per component
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enumerator QT_8bit_uniform
same, shared range for all dimensions
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enumerator QT_4bit_uniform
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enumerator QT_fp16
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enumerator QT_8bit_direct
fast indexing of uint8s
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enumerator QT_6bit
6 bits per component
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enumerator QT_8bit
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enum RangeStat
The uniform encoder can estimate the range of representable values of the unform encoder using different statistics. Here rs = rangestat_arg
Values:
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enumerator RS_minmax
[min - rs*(max-min), max + rs*(max-min)]
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enumerator RS_meanstd
[mean - std * rs, mean + std * rs]
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enumerator RS_quantiles
[Q(rs), Q(1-rs)]
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enumerator RS_optim
alternate optimization of reconstruction error
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enumerator RS_minmax
Public Functions
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ScalarQuantizer(size_t d, QuantizerType qtype)
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ScalarQuantizer()
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void set_derived_sizes()
updates internal values based on qtype and d
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virtual void train(size_t n, const float *x) override
Train the quantizer
- Parameters:
x – training vectors, size n * d
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virtual void compute_codes(const float *x, uint8_t *codes, size_t n) const override
Encode a set of vectors
- Parameters:
x – vectors to encode, size n * d
codes – output codes, size n * code_size
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virtual void decode(const uint8_t *code, float *x, size_t n) const override
Decode a set of vectors
- Parameters:
codes – codes to decode, size n * code_size
x – output vectors, size n * d
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SQuantizer *select_quantizer() const
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SQDistanceComputer *get_distance_computer(MetricType metric = METRIC_L2) const
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InvertedListScanner *select_InvertedListScanner(MetricType mt, const Index *quantizer, bool store_pairs, const IDSelector *sel, bool by_residual = false) const
Public Members
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QuantizerType qtype = QT_8bit
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float rangestat_arg = 0
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size_t bits = 0
bits per scalar code
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struct SQDistanceComputer : public faiss::FlatCodesDistanceComputer
Public Functions
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inline SQDistanceComputer()
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virtual float query_to_code(const uint8_t *code) const = 0
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inline virtual float distance_to_code(const uint8_t *code) final
compute distance of current query to an encoded vector
Public Members
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const float *q
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inline SQDistanceComputer()
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struct SQuantizer
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enum QuantizerType
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struct ScalarQuantizer : public faiss::Quantizer