transform.h

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// Copyright (c) 2021, Aalto University, developed by Erik Schultheis
// All rights reserved.
//
// SPDX-License-Identifier: MIT
 
#ifndef DISMEC_SRC_DATA_TRANSFORM_H
#define DISMEC_SRC_DATA_TRANSFORM_H
 
#include "data/types.h"
#include "matrix_types.h"
 
namespace dismec {
 
    void augment_features_with_bias(DatasetBase& data, real_t bias = 1);
    SparseFeatures augment_features_with_bias(const SparseFeatures& features, real_t bias = 1);
    DenseFeatures augment_features_with_bias(const DenseFeatures& features, real_t bias = 1);
 
    DenseRealVector get_mean_feature(const GenericFeatureMatrix& features);
    DenseRealVector get_mean_feature(const SparseFeatures& features);
    DenseRealVector get_mean_feature(const DenseFeatures& features);
 
    std::vector<long> count_features(const SparseFeatures& features);
 
    void normalize_instances(DatasetBase& data);
    void normalize_instances(SparseFeatures& features);
    void normalize_instances(DenseFeatures& features);
 
    Eigen::PermutationMatrix<Eigen::Dynamic, Eigen::Dynamic, int> sort_features_by_frequency(DatasetBase& data);
    Eigen::PermutationMatrix<Eigen::Dynamic, Eigen::Dynamic, int> sort_features_by_frequency(SparseFeatures& features);
    Eigen::PermutationMatrix<Eigen::Dynamic, Eigen::Dynamic, int> sort_features_by_frequency(DenseFeatures& features);
 
    void hash_sparse_features(SparseFeatures& features, unsigned seed, int buckets, int repeats);
 
    SparseFeatures shortlist_features(const SparseFeatures& source, const std::vector<long>& shortlist);
    DenseFeatures shortlist_features(const DenseFeatures& source, const std::vector<long>& shortlist);
 
    enum class DatasetTransform {
        IDENTITY,           // x
        ONE_PLUS_LOG,       // 1 + log(x)
        LOG_ONE_PLUS,       // log(1+x)
        SQRT,
    };
 
    void transform_features(DatasetBase& data, DatasetTransform transform);
    void transform_features(SparseFeatures& features, DatasetTransform transform);
    void transform_features(DenseFeatures& features, DatasetTransform transform);
}
 
#endif //DISMEC_SRC_DATA_TRANSFORM_H