|
| 1 | +""" |
| 2 | +Semi-Supervised Learning using USB built upon PyTorch |
| 3 | +============================= |
| 4 | +
|
| 5 | +
|
| 6 | +**Author**: `Hao Chen <https://github.com/Hhhhhhao>`_ |
| 7 | + |
| 8 | +
|
| 9 | +Introduction |
| 10 | +------------ |
| 11 | +
|
| 12 | +USB is a semi-supervised learning framework built upon PyTorch. |
| 13 | +Based on Datasets and Modules provided by PyTorch, USB becomes a flexible, modular, and easy-to-use framework for semi-supervised learning. |
| 14 | +It supports a variety of semi-supervised learning algorithms, including FixMatch, FreeMatch, DeFixMatch, SoftMatch, etc. |
| 15 | +It also supports a variety of imbalanced semi-supervised learning algorithms. |
| 16 | +The benchmark results across different datasets of computer vision, natural language processing, and speech processing are included in USB. |
| 17 | +
|
| 18 | +This tutorial will walk you through the basics of using the usb lighting package. |
| 19 | +Let's get started by training a FreeMatch/SoftMatch model on CIFAR-10 using pre-trained ViT! |
| 20 | +And we will show it is easy to change the semi-supervised algorithm and train on imbalanced datasets. |
| 21 | +
|
| 22 | + |
| 23 | +.. figure:: /_static/img/usb_semisup_learn/code.png |
| 24 | + :alt: USB framework illustration |
| 25 | +""" |
| 26 | + |
| 27 | + |
| 28 | +###################################################################### |
| 29 | +# Introduction to FreeMatch and SoftMatch in Semi-Supervised Learning |
| 30 | +# -------------------- |
| 31 | +# Here we provide a brief introduction to FreeMatch and SoftMatch. |
| 32 | +# First we introduce a famous baseline for semi-supervised learning called FixMatch. |
| 33 | +# FixMatch is a very simple framework for semi-supervised learning, where it utilizes a strong augmentation to generate pseudo labels for unlabeled data. |
| 34 | +# It adopts a confidence thresholding strategy to filter out the low-confidence pseudo labels with a fixed threshold set. |
| 35 | +# FreeMatch and SoftMatch are two algorithms that improve upon FixMatch. |
| 36 | +# FreeMatch proposes adaptive thresholding strategy to replace the fixed thresholding strategy in FixMatch. |
| 37 | +# The adaptive thresholding progressively increases the threshold according to the learning status of the model on each class. |
| 38 | +# SoftMatch absorbs the idea of confidence thresholding as an weighting mechanism. |
| 39 | +# It proposes a Gaussian weighting mechanism to overcome the quantity-quality trade-off in pseudo-labels. |
| 40 | +# In this tutorial, we will use USB to train FreeMatch and SoftMatch. |
| 41 | + |
| 42 | + |
| 43 | +###################################################################### |
| 44 | +# Use USB to Train FreeMatch/SoftMatch on CIFAR-10 with only 40 labels |
| 45 | +# -------------------- |
| 46 | +# USB is a Pytorch-based Python package for Semi-Supervised Learning (SSL). |
| 47 | +# It is easy-to-use/extend, affordable to small groups, and comprehensive for developing and evaluating SSL algorithms. |
| 48 | +# USB provides the implementation of 14 SSL algorithms based on Consistency Regularization, and 15 tasks for evaluation from CV, NLP, and Audio domain. |
| 49 | +# It has a modular design that allows users to easily extend the package by adding new algorithms and tasks. |
| 50 | +# It also supports a python api for easier adaptation to different SSL algorithms on new data. |
| 51 | +# |
| 52 | +# |
| 53 | +# Now, let's use USB to train FreeMatch and SoftMatch on CIFAR-10. |
| 54 | +# First, we need to install USB package ``semilearn`` and import necessary api functions from USB. |
| 55 | +# Below is a list of functions we will use from ``semilearn``: |
| 56 | +# - ``get_dataset`` to load dataset, here we use CIFAR-10 |
| 57 | +# - ``get_data_loader`` to create train (labeled and unlabeled) and test data loaders, the train unlabeled loaders will provide both strong and weak augmentation of unlabeled data |
| 58 | +# - ``get_net_builder`` to create a model, here we use pre-trained ViT |
| 59 | +# - ``get_algorithm`` to create the semi-supervised learning algorithm, here we use FreeMatch and SoftMatch |
| 60 | +# - ``get_config``: to get default configuration of the algorithm |
| 61 | +# - ``Trainer``: a Trainer class for training and evaluating the algorithm on dataset |
| 62 | +# |
| 63 | +import semilearn |
| 64 | +from semilearn import get_dataset, get_data_loader, get_net_builder, get_algorithm, get_config, Trainer |
| 65 | + |
| 66 | +###################################################################### |
| 67 | +# After importing necessary functions, we first set the hyper-parameters of the algorithm. |
| 68 | +# |
| 69 | +config = { |
| 70 | + 'algorithm': 'freematch', |
| 71 | + 'net': 'vit_tiny_patch2_32', |
| 72 | + 'use_pretrain': True, |
| 73 | + 'pretrain_path': 'https://github.com/microsoft/Semi-supervised-learning/releases/download/v.0.0.0/vit_tiny_patch2_32_mlp_im_1k_32.pth', |
| 74 | + |
| 75 | + # optimization configs |
| 76 | + 'epoch': 1, |
| 77 | + 'num_train_iter': 4000, |
| 78 | + 'num_eval_iter': 500, |
| 79 | + 'num_log_iter': 50, |
| 80 | + 'optim': 'AdamW', |
| 81 | + 'lr': 5e-4, |
| 82 | + 'layer_decay': 0.5, |
| 83 | + 'batch_size': 16, |
| 84 | + 'eval_batch_size': 16, |
| 85 | + |
| 86 | + |
| 87 | + # dataset configs |
| 88 | + 'dataset': 'cifar10', |
| 89 | + 'num_labels': 40, |
| 90 | + 'num_classes': 10, |
| 91 | + 'img_size': 32, |
| 92 | + 'crop_ratio': 0.875, |
| 93 | + 'data_dir': './data', |
| 94 | + 'ulb_samples_per_class': None, |
| 95 | + |
| 96 | + # algorithm specific configs |
| 97 | + 'hard_label': True, |
| 98 | + 'T': 0.5, |
| 99 | + 'ema_p': 0.999, |
| 100 | + 'ent_loss_ratio': 0.001, |
| 101 | + 'uratio': 2, |
| 102 | + 'ulb_loss_ratio': 1.0, |
| 103 | + |
| 104 | + # device configs |
| 105 | + 'gpu': 0, |
| 106 | + 'world_size': 1, |
| 107 | + 'distributed': False, |
| 108 | + "num_workers": 4, |
| 109 | +} |
| 110 | +config = get_config(config) |
| 111 | + |
| 112 | + |
| 113 | +###################################################################### |
| 114 | +# Then, we load the dataset and create data loaders for training and testing. |
| 115 | +# And we specify the model and algorithm to use. |
| 116 | +# |
| 117 | +dataset_dict = get_dataset(config, config.algorithm, config.dataset, config.num_labels, config.num_classes, data_dir=config.data_dir, include_lb_to_ulb=config.include_lb_to_ulb) |
| 118 | +train_lb_loader = get_data_loader(config, dataset_dict['train_lb'], config.batch_size) |
| 119 | +train_ulb_loader = get_data_loader(config, dataset_dict['train_ulb'], int(config.batch_size * config.uratio)) |
| 120 | +eval_loader = get_data_loader(config, dataset_dict['eval'], config.eval_batch_size) |
| 121 | +algorithm = get_algorithm(config, get_net_builder(config.net, from_name=False), tb_log=None, logger=None) |
| 122 | + |
| 123 | + |
| 124 | +###################################################################### |
| 125 | +# We can start Train the algorithms on CIFAR-10 with 40 labels now. |
| 126 | +# We train for 4000 iterations and evaluate every 500 iterations. |
| 127 | +# |
| 128 | +trainer = Trainer(config, algorithm) |
| 129 | +trainer.fit(train_lb_loader, train_ulb_loader, eval_loader) |
| 130 | + |
| 131 | + |
| 132 | +###################################################################### |
| 133 | +# Finally, let's evaluate the trained model on validation set. |
| 134 | +# After training 4000 iterations with FreeMatch on only 40 labels of CIFAR-10, we obtain a classifier that achieves above 93 accuracy on validation set. |
| 135 | +trainer.evaluate(eval_loader) |
| 136 | + |
| 137 | + |
| 138 | + |
| 139 | +###################################################################### |
| 140 | +# Use USB to Train SoftMatch with specific imbalanced algorithm on imbalanced CIFAR-10 |
| 141 | +# -------------------- |
| 142 | +# |
| 143 | +# Now let's say we have imbalanced labeled set and unlabeled set of CIFAR-10, and we want to train a SoftMatch model on it. |
| 144 | +# We create an imbalanced labeled set and imbalanced unlabeled set of CIFAR-10, by setting the ``lb_imb_ratio`` and ``ulb_imb_ratio`` to 10. |
| 145 | +# Also we replace the ``algorithm`` with ``softmatch`` and set the ``imbalanced`` to ``True``. |
| 146 | +# |
| 147 | +config = { |
| 148 | + 'algorithm': 'softmatch', |
| 149 | + 'net': 'vit_tiny_patch2_32', |
| 150 | + 'use_pretrain': True, |
| 151 | + 'pretrain_path': 'https://github.com/microsoft/Semi-supervised-learning/releases/download/v.0.0.0/vit_tiny_patch2_32_mlp_im_1k_32.pth', |
| 152 | + |
| 153 | + # optimization configs |
| 154 | + 'epoch': 1, |
| 155 | + 'num_train_iter': 4000, |
| 156 | + 'num_eval_iter': 500, |
| 157 | + 'num_log_iter': 50, |
| 158 | + 'optim': 'AdamW', |
| 159 | + 'lr': 5e-4, |
| 160 | + 'layer_decay': 0.5, |
| 161 | + 'batch_size': 16, |
| 162 | + 'eval_batch_size': 16, |
| 163 | + |
| 164 | + |
| 165 | + # dataset configs |
| 166 | + 'dataset': 'cifar10', |
| 167 | + 'num_labels': 1500, |
| 168 | + 'num_classes': 10, |
| 169 | + 'img_size': 32, |
| 170 | + 'crop_ratio': 0.875, |
| 171 | + 'data_dir': './data', |
| 172 | + 'ulb_samples_per_class': None, |
| 173 | + 'lb_imb_ratio': 10, |
| 174 | + 'ulb_imb_ratio': 10, |
| 175 | + 'ulb_num_labels': 3000, |
| 176 | + |
| 177 | + # algorithm specific configs |
| 178 | + 'hard_label': True, |
| 179 | + 'T': 0.5, |
| 180 | + 'ema_p': 0.999, |
| 181 | + 'ent_loss_ratio': 0.001, |
| 182 | + 'uratio': 2, |
| 183 | + 'ulb_loss_ratio': 1.0, |
| 184 | + |
| 185 | + # device configs |
| 186 | + 'gpu': 0, |
| 187 | + 'world_size': 1, |
| 188 | + 'distributed': False, |
| 189 | + "num_workers": 4, |
| 190 | +} |
| 191 | +config = get_config(config) |
| 192 | + |
| 193 | +###################################################################### |
| 194 | +# Then, we re-load the dataset and create data loaders for training and testing. |
| 195 | +# And we specify the model and algorithm to use. |
| 196 | +# |
| 197 | +dataset_dict = get_dataset(config, config.algorithm, config.dataset, config.num_labels, config.num_classes, data_dir=config.data_dir, include_lb_to_ulb=config.include_lb_to_ulb) |
| 198 | +train_lb_loader = get_data_loader(config, dataset_dict['train_lb'], config.batch_size) |
| 199 | +train_ulb_loader = get_data_loader(config, dataset_dict['train_ulb'], int(config.batch_size * config.uratio)) |
| 200 | +eval_loader = get_data_loader(config, dataset_dict['eval'], config.eval_batch_size) |
| 201 | +algorithm = get_algorithm(config, get_net_builder(config.net, from_name=False), tb_log=None, logger=None) |
| 202 | + |
| 203 | + |
| 204 | +###################################################################### |
| 205 | +# We can start Train the algorithms on CIFAR-10 with 40 labels now. |
| 206 | +# We train for 4000 iterations and evaluate every 500 iterations. |
| 207 | +# |
| 208 | +trainer = Trainer(config, algorithm) |
| 209 | +trainer.fit(train_lb_loader, train_ulb_loader, eval_loader) |
| 210 | + |
| 211 | + |
| 212 | +###################################################################### |
| 213 | +# Finally, let's evaluate the trained model on validation set. |
| 214 | +# |
| 215 | +trainer.evaluate(eval_loader) |
| 216 | + |
| 217 | + |
| 218 | + |
| 219 | +###################################################################### |
| 220 | +# References |
| 221 | +# [1] USB: https://github.com/microsoft/Semi-supervised-learning |
| 222 | +# [2] Kihyuk Sohn et al. FixMatch: Simplifying Semi-Supervised Learning with Consistency and Confidence |
| 223 | +# [3] Yidong Wang et al. FreeMatch: Self-adaptive Thresholding for Semi-supervised Learning |
| 224 | +# [4] Hao Chen et al. SoftMatch: Addressing the Quantity-Quality Trade-off in Semi-supervised Learning |
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