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| 1 | +/* |
| 2 | + * Copyright (C) 2018 The Android Open Source Project |
| 3 | + * |
| 4 | + * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | + * you may not use this file except in compliance with the License. |
| 6 | + * You may obtain a copy of the License at |
| 7 | + * |
| 8 | + * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | + * |
| 10 | + * Unless required by applicable law or agreed to in writing, software |
| 11 | + * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | + * See the License for the specific language governing permissions and |
| 14 | + * limitations under the License. |
| 15 | + */ |
| 16 | + |
| 17 | +#ifndef NLP_SAFT_COMPONENTS_COMMON_MOBILE_EMBEDDING_FEATURE_EXTRACTOR_H_ |
| 18 | +#define NLP_SAFT_COMPONENTS_COMMON_MOBILE_EMBEDDING_FEATURE_EXTRACTOR_H_ |
| 19 | + |
| 20 | +#include <memory> |
| 21 | +#include <string> |
| 22 | +#include <vector> |
| 23 | + |
| 24 | +#include "lang_id/common/fel/feature-extractor.h" |
| 25 | +#include "lang_id/common/fel/task-context.h" |
| 26 | +#include "lang_id/common/fel/workspace.h" |
| 27 | +#include "lang_id/common/lite_base/attributes.h" |
| 28 | + |
| 29 | +namespace libtextclassifier3 { |
| 30 | +namespace mobile { |
| 31 | + |
| 32 | +// An EmbeddingFeatureExtractor manages the extraction of features for |
| 33 | +// embedding-based models. It wraps a sequence of underlying classes of feature |
| 34 | +// extractors, along with associated predicate maps. Each class of feature |
| 35 | +// extractors is associated with a name, e.g., "words", "labels", "tags". |
| 36 | +// |
| 37 | +// The class is split between a generic abstract version, |
| 38 | +// GenericEmbeddingFeatureExtractor (that can be initialized without knowing the |
| 39 | +// signature of the ExtractFeatures method) and a typed version. |
| 40 | +// |
| 41 | +// The predicate maps must be initialized before use: they can be loaded using |
| 42 | +// Read() or updated via UpdateMapsForExample. |
| 43 | +class GenericEmbeddingFeatureExtractor { |
| 44 | + public: |
| 45 | + // Constructs this GenericEmbeddingFeatureExtractor. |
| 46 | + // |
| 47 | + // |arg_prefix| is a string prefix for the relevant TaskContext parameters, to |
| 48 | + // avoid name clashes. See GetParamName(). |
| 49 | + explicit GenericEmbeddingFeatureExtractor(const std::string &arg_prefix) |
| 50 | + : arg_prefix_(arg_prefix) {} |
| 51 | + |
| 52 | + virtual ~GenericEmbeddingFeatureExtractor() {} |
| 53 | + |
| 54 | + // Sets/inits up predicate maps and embedding space names that are common for |
| 55 | + // all embedding based feature extractors. |
| 56 | + // |
| 57 | + // Returns true on success, false otherwise. |
| 58 | + SAFTM_MUST_USE_RESULT virtual bool Setup(TaskContext *context); |
| 59 | + SAFTM_MUST_USE_RESULT virtual bool Init(TaskContext *context); |
| 60 | + |
| 61 | + // Requests workspace for the underlying feature extractors. This is |
| 62 | + // implemented in the typed class. |
| 63 | + virtual void RequestWorkspaces(WorkspaceRegistry *registry) = 0; |
| 64 | + |
| 65 | + // Returns number of embedding spaces. |
| 66 | + int NumEmbeddings() const { return embedding_dims_.size(); } |
| 67 | + |
| 68 | + const std::vector<std::string> &embedding_fml() const { |
| 69 | + return embedding_fml_; |
| 70 | + } |
| 71 | + |
| 72 | + // Get parameter name by concatenating the prefix and the original name. |
| 73 | + std::string GetParamName(const std::string ¶m_name) const { |
| 74 | + std::string full_name = arg_prefix_; |
| 75 | + full_name.push_back('_'); |
| 76 | + full_name.append(param_name); |
| 77 | + return full_name; |
| 78 | + } |
| 79 | + |
| 80 | + private: |
| 81 | + // Prefix for TaskContext parameters. |
| 82 | + const std::string arg_prefix_; |
| 83 | + |
| 84 | + // Embedding space names for parameter sharing. |
| 85 | + std::vector<std::string> embedding_names_; |
| 86 | + |
| 87 | + // FML strings for each feature extractor. |
| 88 | + std::vector<std::string> embedding_fml_; |
| 89 | + |
| 90 | + // Size of each of the embedding spaces (maximum predicate id). |
| 91 | + std::vector<int> embedding_sizes_; |
| 92 | + |
| 93 | + // Embedding dimensions of the embedding spaces (i.e. 32, 64 etc.) |
| 94 | + std::vector<int> embedding_dims_; |
| 95 | +}; |
| 96 | + |
| 97 | +// Templated, object-specific implementation of the |
| 98 | +// EmbeddingFeatureExtractor. EXTRACTOR should be a FeatureExtractor<OBJ, |
| 99 | +// ARGS...> class that has the appropriate FeatureTraits() to ensure that |
| 100 | +// locator type features work. |
| 101 | +// |
| 102 | +// Note: for backwards compatibility purposes, this always reads the FML spec |
| 103 | +// from "<prefix>_features". |
| 104 | +template <class EXTRACTOR, class OBJ, class... ARGS> |
| 105 | +class EmbeddingFeatureExtractor : public GenericEmbeddingFeatureExtractor { |
| 106 | + public: |
| 107 | + // Constructs this EmbeddingFeatureExtractor. |
| 108 | + // |
| 109 | + // |arg_prefix| is a string prefix for the relevant TaskContext parameters, to |
| 110 | + // avoid name clashes. See GetParamName(). |
| 111 | + explicit EmbeddingFeatureExtractor(const std::string &arg_prefix) |
| 112 | + : GenericEmbeddingFeatureExtractor(arg_prefix) {} |
| 113 | + |
| 114 | + // Sets up all predicate maps, feature extractors, and flags. |
| 115 | + SAFTM_MUST_USE_RESULT bool Setup(TaskContext *context) override { |
| 116 | + if (!GenericEmbeddingFeatureExtractor::Setup(context)) { |
| 117 | + return false; |
| 118 | + } |
| 119 | + feature_extractors_.resize(embedding_fml().size()); |
| 120 | + for (int i = 0; i < embedding_fml().size(); ++i) { |
| 121 | + feature_extractors_[i].reset(new EXTRACTOR()); |
| 122 | + if (!feature_extractors_[i]->Parse(embedding_fml()[i])) return false; |
| 123 | + if (!feature_extractors_[i]->Setup(context)) return false; |
| 124 | + } |
| 125 | + return true; |
| 126 | + } |
| 127 | + |
| 128 | + // Initializes resources needed by the feature extractors. |
| 129 | + SAFTM_MUST_USE_RESULT bool Init(TaskContext *context) override { |
| 130 | + if (!GenericEmbeddingFeatureExtractor::Init(context)) return false; |
| 131 | + for (auto &feature_extractor : feature_extractors_) { |
| 132 | + if (!feature_extractor->Init(context)) return false; |
| 133 | + } |
| 134 | + return true; |
| 135 | + } |
| 136 | + |
| 137 | + // Requests workspaces from the registry. Must be called after Init(), and |
| 138 | + // before Preprocess(). |
| 139 | + void RequestWorkspaces(WorkspaceRegistry *registry) override { |
| 140 | + for (auto &feature_extractor : feature_extractors_) { |
| 141 | + feature_extractor->RequestWorkspaces(registry); |
| 142 | + } |
| 143 | + } |
| 144 | + |
| 145 | + // Must be called on the object one state for each sentence, before any |
| 146 | + // feature extraction (e.g., UpdateMapsForExample, ExtractFeatures). |
| 147 | + void Preprocess(WorkspaceSet *workspaces, OBJ *obj) const { |
| 148 | + for (auto &feature_extractor : feature_extractors_) { |
| 149 | + feature_extractor->Preprocess(workspaces, obj); |
| 150 | + } |
| 151 | + } |
| 152 | + |
| 153 | + // Extracts features using the extractors. Note that features must already |
| 154 | + // be initialized to the correct number of feature extractors. No predicate |
| 155 | + // mapping is applied. |
| 156 | + void ExtractFeatures(const WorkspaceSet &workspaces, const OBJ &obj, |
| 157 | + ARGS... args, |
| 158 | + std::vector<FeatureVector> *features) const { |
| 159 | + // DCHECK(features != nullptr); |
| 160 | + // DCHECK_EQ(features->size(), feature_extractors_.size()); |
| 161 | + for (int i = 0; i < feature_extractors_.size(); ++i) { |
| 162 | + (*features)[i].clear(); |
| 163 | + feature_extractors_[i]->ExtractFeatures(workspaces, obj, args..., |
| 164 | + &(*features)[i]); |
| 165 | + } |
| 166 | + } |
| 167 | + |
| 168 | + private: |
| 169 | + // Templated feature extractor class. |
| 170 | + std::vector<std::unique_ptr<EXTRACTOR>> feature_extractors_; |
| 171 | +}; |
| 172 | + |
| 173 | +} // namespace mobile |
| 174 | +} // namespace nlp_saft |
| 175 | + |
| 176 | +#endif // NLP_SAFT_COMPONENTS_COMMON_MOBILE_EMBEDDING_FEATURE_EXTRACTOR_H_ |
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