SimCLR/README.md

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# PyTorch SimCLR: A Simple Framework for Contrastive Learning of Visual Representations
### Blog post with full documentation: [Exploring SimCLR: A Simple Framework for Contrastive Learning of Visual Representations](https://sthalles.github.io/simple-self-supervised-learning/)
![Image of SimCLR Arch](https://sthalles.github.io/assets/contrastive-self-supervised/cover.png)
### See also [PyTorch Implementation for BYOL - Bootstrap Your Own Latent: A New Approach to Self-Supervised Learning](https://github.com/sthalles/PyTorch-BYOL).
## Installation
```
$ conda env create --name simclr --file env.yml
$ conda activate simclr
$ python run.py
```
## Config file
Before running SimCLR, make sure you choose the correct running configurations on the ```config.yaml``` file.
```yaml
# A batch size of N, produces 2 * (N-1) negative samples. Original implementation uses a batch size of 8192
batch_size: 512
# Number of epochs to train
epochs: 40
# Frequency to eval the similarity score using the validation set
eval_every_n_epochs: 1
# Specify a folder containing a pre-trained model to fine-tune. If training from scratch, pass None.
fine_tune_from: 'resnet-18_80-epochs'
# Frequency to which tensorboard is updated
log_every_n_steps: 50
# l2 Weight decay magnitude, original implementation uses 10e-6
weight_decay: 10e-6
# if True, training is done using mixed precision. Apex needs to be installed in this case.
fp16_precision: False
# Model related parameters
model:
# Output dimensionality of the embedding vector z. Original implementation uses 2048
out_dim: 256
# The ConvNet base model. Choose one of: "resnet18" or "resnet50". Original implementation uses resnet50
base_model: "resnet18"
# Dataset related parameters
dataset:
s: 1
# dataset input shape. For datasets containing images of different size, this defines the final
input_shape: (96,96,3)
# Number of workers for the data loader
num_workers: 0
# Size of the validation set in percentage
valid_size: 0.05
# NTXent loss related parameters
loss:
# Temperature parameter for the contrastive objective
temperature: 0.5
# Distance metric for contrastive loss. If False, uses dot product. Original implementation uses cosine similarity.
use_cosine_similarity: True
```
## Feature Evaluation
Feature evaluation is done using a linear model protocol.
Features are learned using the ```STL10 train+unsupervised``` set and evaluated in the ```test``` set;
Check the [![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://github.com/sthalles/SimCLR/blob/master/feature_eval/linear_feature_eval.ipynb) notebook for reproducibility.
| Linear Classifier | Feature Extractor | Architecture | Feature dimensionality | Projection Head dimensionality | Epochs | STL10 Top 1 |
|:---------------------------:|:-----------------:|:------------:|:----------------------:|:-------------------------------:|:------:|:-----------:|
| Logistic Regression | PCA Features | - | 256 | - | | 36.0% |
| KNN | PCA Features | - | 256 | - | | 31.8% |
| Logistic Regression (LBFGS) | SimCLR | [ResNet-18](https://drive.google.com/open?id=1c4eVon0sUd-ChVhH6XMpF6nCngNJsAPk) | 512 | 256 | 40 | 70.3% |
| KNN | SimCLR | ResNet-18 | 512 | 256 | 40 | 66.2% |
| Logistic Regression (LBFGS) | SimCLR | [ResNet-18](https://drive.google.com/open?id=1L0yoeY9i2mzDcj69P4slTWb-cfr3PyoT) | 512 | 256 | 80 | 72.9% |
| KNN | SimCLR | ResNet-18 | 512 | 256 | 80 | 69.8% |
| Logistic Regression (Adam) | SimCLR | [ResNet-18](https://drive.google.com/open?id=1aZ12TITXnajZ6QWmS_SDm8Sp8gXNbeCQ) | 512 | 256 | 100 | 75.4% |
| Logistic Regression (Adam) | SimCLR | [ResNet-50](https://drive.google.com/open?id=1TZqBNTFCsO-mxAiR-zJeyupY-J2gA27Q) | 2048 | 128 | 40 | 74.6% |
| Logistic Regression (Adam) | SimCLR | [ResNet-50](https://drive.google.com/open?id=1is1wkBRccHdhSKQnPUTQoaFkVNSaCb35) | 2048 | 128 | 80 | 77.3% |