Model reference · open weights

cross-en-de-roberta-sentence-transformer

Available as managed deployment Embeddings T-Systems-onsite Embeddings 1 variants 11k dl/mo

cross-en-de-roberta-sentence-transformer is an open-weight embedding model from T-Systems-onsite. 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 byT-Systems-onsite
TypeEmbedding models
TaskEmbeddings
Parameters (lead)278M
Context514 tokens
Runs withtransformers
Released2022-03-02
Popularity11k downloads / month
LicenceOpen weights

About

What cross-en-de-roberta-sentence-transformer is

This model is intended to compute sentence (text) embeddings for English and German text. These embeddings can then be compared with cosine-similarity to find sentences with a similar semantic meaning. For example this can be useful for semantic textual similarity, semantic search, or paraphrase mining. To do this you have to use the Sentence Transformers Python framework.

Read the full model card

The speciality of this model is that it also works cross-lingually. Regardless of the language, the sentences are translated into very similar vectors according to their semantics. This means that you can, for example, enter a search in German and find results according to the semantics in German and also in English. Using a xlm model and multilingual finetuning with language-crossing we reach performance that even exceeds the best current dedicated English large model (see Evaluation section below).

Sentence-BERT (SBERT) is a modification of the pretrained BERT network that use siamese and triplet network structures to derive semantically meaningful sentence embeddings that can be compared using cosine-similarity. This reduces the effort for finding the most similar pair from 65hours with BERT / RoBERTa to about 5 seconds with SBERT, while maintaining the accuracy from BERT.

Source: Sentence-BERT: Sentence Embeddings using Siamese BERT-Networks

This model is fine-tuned from Philip May and open-sourced by T-Systems-onsite. Special thanks to Nils Reimers for your awesome open-source work, the Sentence Transformers, the models and your help on GitHub.

How to use

To use this model install the sentence-transformers package (see here: ).

from sentence_transformers import SentenceTransformer
model = SentenceTransformer('T-Systems-onsite/cross-en-de-roberta-sentence-transformer')

For details of usage and examples see here:

Training

The base model is xlm-roberta-base. This model has been further trained by Nils Reimers on a large scale paraphrase dataset for 50+ languages. Nils Reimers about this on GitHub:

A paper is upcoming for the paraphrase models.

These models were trained on various datasets with Millions of examples for paraphrases, mainly derived from Wikipedia edit logs, paraphrases mined from Wikipedia and SimpleWiki, paraphrases from news reports, AllNLI-entailment pairs with in-batch-negative loss etc.

In internal tests, they perform much better than the NLI+STSb models as they have see more and broader type of training data. NLI+STSb has the issue that they are rather narrow in their domain and do not contain any domain specific words / sentences (like from chemistry, computer science, math etc.). The paraphrase models has seen plenty of sentences from various domains.

More details with the setup, all the datasets, and a wider evaluation will follow soon.

The resulting model called xlm-r-distilroberta-base-paraphrase-v1 has been released here:

Building on this cross language model we fine-tuned it for English and German language on the STSbenchmark dataset. For German language we used the dataset of our German STSbenchmark dataset which has been translated with deepl.com. Additionally to the German and English training samples we generated samples of English and German crossed. We call this multilingual finetuning with language-crossing. It doubled the traing-datasize and tests show that it further improves performance.

We did an automatic hyperparameter search for 33 trials with Optuna. Using 10-fold crossvalidation on the deepl.com test and dev dataset we found the following best hyperparameters:

  • batch_size = 8
  • num_epochs = 2
  • lr = 1.026343323298136e-05,
  • eps = 4.462251033010287e-06
  • weight_decay = 0.04794438776350409
  • warmup_steps_proportion = 0.1609010732760181

The final model was trained with these hyperparameters on the combination of the train and dev datasets from English, German and the crossings of them. The testset was left for testing.

Evaluation

Model NameSpearmanGermanSpearmanEnglishSpearmanEN-DE & DE-EN(cross)
xlm-r-distilroberta-base-paraphrase-v10.80790.83500.7983
xlm-r-100langs-bert-base-nli-stsb-mean-tokens0.78770.84650.7908
xlm-r-bert-base

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 cross-en-de-roberta-sentence-transformer for you, it answers on the OpenAI-compatible API — the same base URL and keys as every other model. (cross-en-de-roberta-sentence-transformer 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":"cross-en-de-roberta-sentence-transformer","input":"text to embed"}'

Create an account — your API key is available in the console. 3M free tokens every 30 days with every new account.

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