File IndexLSH.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.
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 IndexLSH : public faiss::Index
- #include <IndexLSH.h>
The sign of each vector component is put in a binary signature
Public Types
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typedef unsigned char uint8_t
Public Functions
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const float *apply_preprocess(idx_t n, const float *x) const
Preprocesses and resizes the input to the size required to binarize the data
- Parameters
x – input vectors, size n * d
- Returns
output vectors, size n * bits. May be the same pointer as x, otherwise it should be deleted by the caller
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virtual void train(idx_t n, const float *x) override
Perform training on a representative set of vectors
- Parameters
n – nb of training vectors
x – training vecors, size n * d
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virtual void add(idx_t n, const float *x) override
Add n vectors of dimension d to the index.
Vectors are implicitly assigned labels ntotal .. ntotal + n - 1 This function slices the input vectors in chunks smaller than blocksize_add and calls add_core.
- Parameters
x – input matrix, size n * d
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virtual void search(idx_t n, const float *x, idx_t k, float *distances, idx_t *labels) const override
query n vectors of dimension d to the index.
return at most k vectors. If there are not enough results for a query, the result array is padded with -1s.
- Parameters
x – input vectors to search, size n * d
labels – output labels of the NNs, size n*k
distances – output pairwise distances, size n*k
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virtual void reset() override
removes all elements from the database.
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void transfer_thresholds(LinearTransform *vt)
transfer the thresholds to a pre-processing stage (and unset train_thresholds)
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inline ~IndexLSH() override
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IndexLSH()
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virtual size_t sa_code_size() const override
size of the produced codes in bytes
Public Members
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int nbits
nb of bits per vector
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int bytes_per_vec
nb of 8-bits per encoded vector
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bool rotate_data
whether to apply a random rotation to input
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bool train_thresholds
whether we train thresholds or use 0
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RandomRotationMatrix rrot
optional random rotation
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std::vector<float> thresholds
thresholds to compare with
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typedef unsigned char uint8_t
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struct IndexLSH : public faiss::Index