Struct faiss::ITQMatrix
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struct ITQMatrix : public faiss::LinearTransform
ITQ implementation from
Iterative quantization: A procrustean approach to learning binary codes for large-scale image retrieval,
Yunchao Gong, Svetlana Lazebnik, Albert Gordo, Florent Perronnin, PAMI’12.
Public Functions
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explicit ITQMatrix(int d = 0)
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virtual void train(idx_t n, const float *x) override
Perform training on a representative set of vectors. Does nothing by default.
- Parameters:
n – nb of training vectors
x – training vecors, size n * d
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virtual void apply_noalloc(idx_t n, const float *x, float *xt) const override
same as apply, but result is pre-allocated
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void transform_transpose(idx_t n, const float *y, float *x) const
compute x = A^T * (x - b) is reverse transform if A has orthonormal lines
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virtual void reverse_transform(idx_t n, const float *xt, float *x) const override
works only if is_orthonormal
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void set_is_orthonormal()
compute A^T * A to set the is_orthonormal flag
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void print_if_verbose(const char *name, const std::vector<double> &mat, int n, int d) const
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virtual void check_identical(const VectorTransform &other) const override
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float *apply(idx_t n, const float *x) const
apply the transformation and return the result in an allocated pointer
- Parameters:
n – number of vectors to transform
x – input vectors, size n * d_in
- Returns:
output vectors, size n * d_out
Public Members
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int max_iter
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int seed
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std::vector<double> init_rotation
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bool have_bias
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bool is_orthonormal
! whether to use the bias term
check if matrix A is orthonormal (enables reverse_transform)
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std::vector<float> A
Transformation matrix, size d_out * d_in.
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std::vector<float> b
bias vector, size d_out
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bool verbose
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int d_in
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int d_out
! input dimension
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bool is_trained
set if the VectorTransform does not require training, or if training is done already
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explicit ITQMatrix(int d = 0)