:books: add documentation

README.md

@@ -4,8 +4,67 @@ tags:
 - sentence-transformers
 - feature-extraction
 - sentence-similarity
+language: en
 ---
 
-# reddit_single-context_mpnet-base
+# Model description
 
-This is a microsoft/mpnet-base model trained on about 700M (context, response) pairs from Reddit 2015-2018. See data_config.json and train_script.py in this respository how the model was trained and which datasets have been used.
+The project aims to train sentence embedding models on very large sentence level datasets using a self-supervised 
+contrastive learning objective. We used the pretrained ['mpnet-base'](https://huggingface.co/microsoft/mpnet-base) model and fine-tuned in on a 
+700M sentence pairs dataset. We use a contrastive learning objective: given a sentence from the pair, the model should predict which out of a set of randomly sampled other sentences, was actually paired with it in our dataset.
+
+We developped this model during the 
+[Community week using JAX/Flax for NLP & CV](https://discuss.huggingface.co/t/open-to-the-community-community-week-using-jax-flax-for-nlp-cv/7104), 
+organized by Hugging Face. We developped this model as part of the project:
+[Train the Best Sentence Embedding Model Ever with 1B Training Pairs](https://discuss.huggingface.co/t/train-the-best-sentence-embedding-model-ever-with-1b-training-pairs/7354). We benefited from efficient hardware infrastructure to run the project: 7 TPUs v3-8, as well
+as intervention from Google’s Flax, JAX, and Cloud team member about efficient deep learning frameworks.
+
+## Intended uses
+
+Our model is intented to be used as a sentence encoder. Given an input sentence, it ouptuts a vector which captures 
+the sentence semantic information. The sentence vector may be used for information retrieval, clustering or sentence 
+similarity tasks.
+
+## How to use
+
+Here is how to use this model to get the features of a given text using [SentenceTransformers](https://github.com/UKPLab/sentence-transformers) library:
+
+```python
+from sentence_transformers import SentenceTransformer
+
+model = SentenceTransformer('flax-sentence-embeddings/all_datasets_v4_mpnet-base')
+text = "Replace me by any text you'd like."
+text_embbedding = model.encode(text)
+# array([-0.01559514,  0.04046123,  0.1317083 ,  0.00085931,  0.04585106,
+#        -0.05607086,  0.0138078 ,  0.03569756,  0.01420381,  0.04266302 ...],
+#        dtype=float32)
+```
+
+# Training procedure
+
+## Pre-training 
+
+We use the pretrained ['mpnet-base'](https://huggingface.co/microsoft/mpnet-base). 
+Please refer to the model card for more detailed information about the pre-training procedure.
+
+## Fine-tuning 
+
+We fine-tune the model using a contrastive objective. Formally, we compute the cosine similarity from each possible sentence pairs from the batch.
+We then apply the cross entropy loss by comparing with true pairs.
+
+### Hyper parameters
+
+We trained ou model on a TPU v3-8. We train the model during 540k steps using a batch size of 1024 (128 per TPU core).
+We use a learning rate warm up of 500. The sequence length was limited to 128 tokens. We used the AdamW optimizer with
+a 2e-5 learning rate. The full training script is accessible in this current repository.
+
+### Training data
+
+We use the concatenation from multiple datasets to fine-tune our model. The total number of sentence pairs is above 700M sentences.
+We sampled each dataset given a weighted probability which configuration is detailed in the `data_config.json` file.
+We only use the first context response when building the dataset.
+
+
+| Dataset                                                  | Paper                                    | Number of training tuples  |
+|:--------------------------------------------------------:|:----------------------------------------:|:--------------------------:|
+| [Reddit conversationnal](https://github.com/PolyAI-LDN/conversational-datasets/tree/master/reddit) | [paper](https://arxiv.org/abs/1904.06472) | 726,484,430 |