Model reference · open weights

dragon-plus-context-encoder

Available as managed deployment Embeddings facebook Embeddings 1 variants 3k dl/mo

dragon-plus-context-encoder is an open-weight embedding model from facebook. AxForge deploys and operates it for you on dedicated EU-owned hardware — with the licence handled where one is required.

Available as managed deployment — configured and operated for you on dedicated EU hardware, quoted per deployment.

What it is

Released byMeta
Published underfacebook
TypeEmbedding models
TaskEmbeddings
Context512 tokens
Runs withtransformers
Released2023-02-15
Popularity3k downloads / month
LicenceUnknown

About

What dragon-plus-context-encoder is

DRAGON+ is a BERT-base sized dense retriever initialized from RetroMAE and further trained on the data augmented from MS MARCO corpus, following the approach described in How to Train Your DRAGON: Diverse Augmentation Towards Generalizable Dense Retrieval.

The associated GitHub repository is available here https://github.com/facebookresearch/dpr-scale/tree/main/dragon. We use asymmetric dual encoder, with two distinctly parameterized encoders. The following models are also available:

Read the full model card
ModelInitializationMARCO DevBEIRQuery Encoder PathContext Encoder Path
DRAGON+Shitao/RetroMAE39.047.4facebook/dragon-plus-query-encoderfacebook/dragon-plus-context-encoder
DRAGON-RoBERTaRoBERTa-base39.447.2facebook/dragon-roberta-query-encoderfacebook/dragon-roberta-context-encoder

Usage (HuggingFace Transformers)

Using the model directly available in HuggingFace transformers .

import torch
from transformers import AutoTokenizer, AutoModel
tokenizer = AutoTokenizer.from_pretrained('facebook/dragon-plus-query-encoder')
query_encoder = AutoModel.from_pretrained('facebook/dragon-plus-query-encoder')
context_encoder = AutoModel.from_pretrained('facebook/dragon-plus-context-encoder')

# We use msmarco query and passages as an example
query =  "Where was Marie Curie born?"
contexts = [
    "Maria Sklodowska, later known as Marie Curie, was born on November 7, 1867.",
    "Born in Paris on 15 May 1859, Pierre Curie was the son of Eugène Curie, a doctor of French Catholic origin from Alsace."
]
# Apply tokenizer
query_input = tokenizer(query, return_tensors='pt')
ctx_input = tokenizer(contexts, padding=True, truncation=True, return_tensors='pt')
# Compute embeddings: take the last-layer hidden state of the [CLS] token
query_emb = query_encoder(**query_input).last_hidden_state[:, 0, :]
ctx_emb = context_encoder(**ctx_input).last_hidden_state[:, 0, :]
# Compute similarity scores using dot product
score1 = query_emb @ ctx_emb[0]  # 396.5625
score2 = query_emb @ ctx_emb[1]  # 393.8340

From the published model card. Full card on the HuggingFace links in the sidebar.

Using it via the API

Call it like any OpenAI endpoint

Once AxForge deploys dragon-plus-context-encoder for you, it answers on the OpenAI-compatible API — the same base URL and keys as every other model. (dragon-plus-context-encoder below is illustrative; you get the exact model name on deployment.)

$ curl -sS https://api.axforge.ai/v1/embeddings \
  -H "Authorization: Bearer $AXFORGE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"dragon-plus-context-encoder","input":"text to embed"}'

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