Merge branch 'master' into am/pytorch_fcn_conversion

Author: vikasgupta-github

Bag-Of-Tricks-For-Image-Classification/README.md

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+## Description
+
+This repository contains classification pipeline for experiments with tricks listed in
+["Bag of Tricks for Image Classification with Convolutional Neural Networks"](https://arxiv.org/abs/1812.01187). Visit [our blogpost](https://www.learnopencv.com/bag-of-tricks-for-image-classification-lets-check-if-it-is-working-or-not/) for more details.
+
+The pipeline is based on [pytorch-lightning framework](https://github.com/PyTorchLightning/pytorch-lightning).
+
+### Installation
+
+1. Clone the repository;
+2. Set up the virtual environment;
+3. If you are going to run experiments with mixed-precision:
+
+   - Check you CUDA version with `nvcc --version`;
+   - Install pytorch 1.5.1 compiled with CUDA version which you have installed. In our case it is CUDA 10.1 so the
+     pytorch should be installed with
+     `pip install torch==1.5.1+cu101 -f https://download.pytorch.org/whl/torch_stable.html`;
+   - Install Nvidia Apex by following [the official instructions](https://github.com/NVIDIA/apex#quick-start);
+     Otherwise:
+   - Run `pip install torch==1.5.1` to install PyTorch
+
+4. Run `pip install -r requirements.txt`
+
+### Dataset
+
+Please, follow the instruction to prepare the dataset:
+
+- Download zip-archive from kaggle ([link](https://www.kaggle.com/dansbecker/food-101/));
+- Unzip the data;
+- Use `split_food-101.py` to split Food-101 into train/test folders. This script will parse `train.txt` and `test.txt`
+  and copy images into corresponding sub-folders. Note that we hard-coded the classes which we are going to use.
+
+### Training
+
+To train model launch
+
+```
+python main.py --gpus [gpus_number] --max_epochs [epoch_number] --data-root [path_to_dataset] --amp_level [optimization_level] (only for mixed-precision with apex)
+```
+
+You can turn on any trick by adding the corresponding key:
+
+```
+--use-smoothing for label smoothing;
+--use-mixup for mixup augmentation;
+--use-cosine-scheduler for Cosine LR Scheduler;
+--use-knowledge-distillation for Knowledge Distillation;
+```
+
+_Note:_ If you want to train the model on GPU you should always use `--gpus` key, without it the pytorch lightning
+console log will show you that the GPU is used but the training will be performed on CPU.
+
+For Knowledge Distillation, please, download the teacher weights from
+[Dropbox](https://www.dropbox.com/s/za5eeyhhy6pmpd2/bag_of_tricks_resnet50_teacher.ckpt?dl=0).
+
+Run `python main.py --help` to see all possible arguments. This command will also show you the arguments for pytorch
+lightning Trainer. Please, see the
+[official documentation](https://pytorch-lightning.readthedocs.io/en/0.8.5/trainer.html#trainer-flags) for details about
+them.
+
+### Testing
+
+To evaluate a trained model launch
+
+```
+python main.py --gpus [gpus_number] --data-root [path_to_dataset] -e --checkpoint [path_to_checkpoint]
+```
+
+### Colab Notebook
+
+You can also train a colab-based version of this model:
+
+[Open in Colab](https://colab.research.google.com/github/spmallick/learnopencv/blob/master/Bag-Of-Tricks-For-Image-Classification/bag-of-tricks-colab.ipynb)
+
+## AI Courses by OpenCV
+
+Want to become an expert in AI? [AI Courses by OpenCV](https://opencv.org/courses/) is a great place to start.
+
+<a href="https://opencv.org/courses/">
+<p align="center">
+<img src="https://www.learnopencv.com/wp-content/uploads/2020/04/AI-Courses-By-OpenCV-Github.png">
+</p>
+</a>