Update README.md

README.md

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 ---
 library_name: transformers
 tags: []
+language:
+- en
+- fr
+- es
+- de
+- el
+- bg
+- ru
+- tr
+- ar
+- vi
+- th
+- zh
+- ai
+- sw
+- ur
+datasets:
+- allenai/c4
 ---
+<div align="center">
 
-# Model Card for Model ID
-
-<!-- Provide a quick summary of what the model is/does. -->
+# Model Card for MrT5 Large
 
+[**MrT5: Dynamic Token Merging for Efficient Byte-level Language Models**](https://arxiv.org/pdf/2410.20771)\
+(Kallini et al., 2024)
 
+</div>
 
-## Model Details
+![](MrT5.png)
 
-### Model Description
+<!-- Provide a quick summary of what the model is/does. -->
 
-<!-- Provide a longer summary of what this model is. -->
+**MrT5** (**M**e**r**ge**T5**) is a more efficient variant of [ByT5 (Xue et al., 2022)](https://arxiv.org/abs/2105.13626) that integrates a token deletion mechanism in its encoder to *dynamically* shorten the input sequence length. After processing through a fixed number of encoder layers, a learned *delete gate* determines which tokens are to be removed and which are to be retained for subsequent layers. By effectively "merging" critical information from deleted tokens into a more compact sequence, MrT5 presents a solution to the practical limitations of existing byte-level models.
+
+## Citation
+
+If you use this model, please cite the MrT5 paper:
+
+```bibtex
+@inproceedings{
+    kallini2025mrt,
+    title={MrT5: Dynamic Token Merging for Efficient Byte-level Language Models},
+    author={Julie Kallini and Shikhar Murty and Christopher D Manning and Christopher Potts and R{\'o}bert Csord{\'a}s},
+    booktitle={The Thirteenth International Conference on Learning Representations},
+    year={2025},
+    url={https://openreview.net/forum?id=VYWBMq1L7H}
+}
+```
+
+Also cite the ByT5 paper:
+
+```bibtex
+@article{xue-etal-2022-byt5,
+    title = "{B}y{T}5: Towards a Token-Free Future with Pre-trained Byte-to-Byte Models",
+    author = "Xue, Linting  and
+      Barua, Aditya  and
+      Constant, Noah  and
+      Al-Rfou, Rami  and
+      Narang, Sharan  and
+      Kale, Mihir  and
+      Roberts, Adam  and
+      Raffel, Colin",
+    editor = "Roark, Brian  and
+      Nenkova, Ani",
+    journal = "Transactions of the Association for Computational Linguistics",
+    volume = "10",
+    year = "2022",
+    address = "Cambridge, MA",
+    publisher = "MIT Press",
+    url = "https://aclanthology.org/2022.tacl-1.17",
+    doi = "10.1162/tacl_a_00461",
+    pages = "291--306",
+}
+```
 
-This is the model card of a 🤗 transformers model that has been pushed on the Hub. This model card has been automatically generated.
 
-- **Developed by:** [More Information Needed]
-- **Funded by [optional]:** [More Information Needed]
-- **Shared by [optional]:** [More Information Needed]
-- **Model type:** [More Information Needed]
-- **Language(s) (NLP):** [More Information Needed]
-- **License:** [More Information Needed]
-- **Finetuned from model [optional]:** [More Information Needed]
+## Model Details
 
-### Model Sources [optional]
+This is the model card for the 300M-parameter **MrT5 Large** (`mrt5-large`), a more efficient variant of ByT5 Large (`google/byt5-large`). This model is trained to reduce sequence lengths by ~50% on average.
 
-<!-- Provide the basic links for the model. -->
+- **Developed by:** Julie Kallini, Shikhar Murty, Christopher D. Manning, Christopher Potts, Róbert Csordás
+- **Model type:** MrT5
+- **Languages:** English, French, Spanish, German, Greek, Bulgarian, Russian, Turkish, Arabic, Vietnamese, Thai, Chinese, Hindi, Swahili, and Urdu
+- **Fine-tuned from model:** [google/byt5-large](https://huggingface.co/google/byt5-large)
+- **Sources for more information**:
+    - [GitHub Repository](https://github.com/jkallini/mrt5)
+    - [Paper](https://arxiv.org/abs/2410.20771)
 
-- **Repository:** [More Information Needed]
-- **Paper [optional]:** [More Information Needed]
-- **Demo [optional]:** [More Information Needed]
+### Model Architecture
 
-## Uses
+MrT5 Large uses the model configuration of the standard ByT5 Large, which has a feed-forward dimensionality of 3840, a model dimensionality of 1536, 36 encoder layers, 12 decoder layers, 16 attention heads in each layer, and 1.23B total parameters.
 
-<!-- Address questions around how the model is intended to be used, including the foreseeable users of the model and those affected by the model. -->
+MrT5 has an additional *delete gate*, which dynamically reduces the encoder sequence length. In this model, it is placed after the third encoder layer, and all subsequent layers operate on a reduced sequence. This model was trained with a deletion rate of δ=0.5, which means that the model reduces its encoder sequence length by ~50% after
+the third layer. MrT5’s gating mechanism only introduces an additional 3,000 parameters.
 
-### Direct Use
+MrT5 Large is initialized from ByT5 Large and fine-tuned on the same training objective. Only MrT5's delete gate is randomly initialized before training.
+The other distinguishing feature of MrT5 is that it uses [softmax1](https://www.evanmiller.org/attention-is-off-by-one.html) in its attention mechanism.
 
-<!-- This section is for the model use without fine-tuning or plugging into a larger ecosystem/app. -->
+## Uses
 
-[More Information Needed]
+This model is an encoder-decoder architecture designed primarily for sequence-to-sequence tasks. While it can be used as-is for exploratory or academic purposes, fine-tuning is recommended to achieve optimal performance on specific downstream tasks.
 
-### Downstream Use [optional]
+To leverage the model’s deletion feature, please use the custom **MrT5Trainer** available in the [accompanying repository](https://github.com/jkallini/mrt5). This specialized trainer ensures that the deletion mechanism is properly maintained and integrated during fine-tuning.
 
-<!-- This section is for the model use when fine-tuned for a task, or when plugged into a larger ecosystem/app -->
+Because this is a base model built for academic and research explorations, it is not intended for production-grade deployments. Users should carefully evaluate the model’s outputs, especially in any setting where reliability and robustness are critical.
 
-[More Information Needed]
+## Bias, Risks, and Limitations
 
-### Out-of-Scope Use
+Language models are known to exhibit various forms of social bias and may produce harmful or offensive content ([Bender et al., 2021](https://dl.acm.org/doi/pdf/10.1145/3442188.3445922); [Bommasani et al., 2022](https://arxiv.org/abs/2108.07258); [Liang et al., 2022](https://arxiv.org/abs/2211.09110)). Like other language models, this model may produce biased or harmful outputs. It has not been fine-tuned for safety and should be used with caution, especially in sensitive contexts.
 
-<!-- This section addresses misuse, malicious use, and uses that the model will not work well for. -->
+## How to Get Started with the Model
 
-[More Information Needed]
+Like ByT5, MrT5 works on raw UTF-8 bytes and can be used without a tokenizer. Make sure to set `trust_remote_code=True` to load the MrT5 code:
 
-## Bias, Risks, and Limitations
+```python
+from transformers import AutoModelForSeq2SeqLM
+import torch
 
-<!-- This section is meant to convey both technical and sociotechnical limitations. -->
+model = AutoModelForSeq2SeqLM.from_pretrained('stanfordnlp/mrt5-large', trust_remote_code=True)
 
-[More Information Needed]
+input_ids = torch.tensor([list("Life is like a box of chocolates.".encode("utf-8"))]) + 3  # add 3 for special tokens
+labels = torch.tensor([list("La vie est comme une boîte de chocolat.".encode("utf-8"))]) + 3  # add 3 for special tokens
 
-### Recommendations
+loss = model(input_ids, labels=labels).loss # forward pass
+```
 
-<!-- This section is meant to convey recommendations with respect to the bias, risk, and technical limitations. -->
+For batched inference and training, you can use ByT5's tokenizer class:
 
-Users (both direct and downstream) should be made aware of the risks, biases and limitations of the model. More information needed for further recommendations.
+```python
+from transformers import AutoModelForSeq2SeqLM, AutoTokenizer
 
-## How to Get Started with the Model
+model = AutoModelForSeq2SeqLM.from_pretrained('stanfordnlp/mrt5-large', trust_remote_code=True)
+tokenizer = AutoTokenizer.from_pretrained('google/byt5-large')
 
-Use the code below to get started with the model.
+model_inputs = tokenizer(["Life is like a box of chocolates.", "Today is Monday."], padding="longest", return_tensors="pt")
+labels = tokenizer(["La vie est comme une boîte de chocolat.", "Aujourd'hui c'est lundi."], padding="longest", return_tensors="pt").input_ids
 
-[More Information Needed]
+loss = model(**model_inputs, labels=labels).loss # forward pass
+```
 
 ## Training Details
 
 ### Training Data
 
-<!-- This should link to a Dataset Card, perhaps with a short stub of information on what the training data is all about as well as documentation related to data pre-processing or additional filtering. -->
-
-[More Information Needed]
+For continued pre-training, we use the [multilingual C4 (mC4) corpus](https://huggingface.co/datasets/allenai/c4) ([Raffel et al., 2020](https://arxiv.org/abs/1910.10683); [Xue et al., 2021](https://arxiv.org/abs/2010.11934)). MrT5 is trained on 15 typologically diverse languages: English, French, Spanish, German, Greek, Bulgarian, Russian, Turkish, Arabic, Vietnamese, Thai, Chinese, Hindi, Swahili, and Urdu.
+To avoid training models for multiple epochs, we ensure that the samples drawn from the mC4 corpus are sufficiently large. Additionally, we extract equal-sized samples for each language (in terms of bytes) from the mC4 training split.
 
 ### Training Procedure
 
-<!-- This relates heavily to the Technical Specifications. Content here should link to that section when it is relevant to the training procedure. -->
-
-#### Preprocessing [optional]
-
-[More Information Needed]
-
-
-#### Training Hyperparameters
-
-- **Training regime:** [More Information Needed] <!--fp32, fp16 mixed precision, bf16 mixed precision, bf16 non-mixed precision, fp16 non-mixed precision, fp8 mixed precision -->
-
-#### Speeds, Sizes, Times [optional]
-
-<!-- This section provides information about throughput, start/end time, checkpoint size if relevant, etc. -->
-
-[More Information Needed]
-
-## Evaluation
-
-<!-- This section describes the evaluation protocols and provides the results. -->
-
-### Testing Data, Factors & Metrics
-
-#### Testing Data
-
-<!-- This should link to a Dataset Card if possible. -->
-
-[More Information Needed]
-
-#### Factors
-
-<!-- These are the things the evaluation is disaggregating by, e.g., subpopulations or domains. -->
-
-[More Information Needed]
+MrT5 is trained on the ByT5 span corruption pre-training objective. In this task, spans of tokens in unlabeled text data are replaced with a single *sentinel token* ID per span, and the model must fill in the missing tokens. For ByT5 and MrT5, these are spans of bytes, and the masks can potentially interfere with word boundaries.
 
-#### Metrics
+#### Preprocessing
 
-<!-- These are the evaluation metrics being used, ideally with a description of why. -->
+When training on the span corruption objective, we calculate the corrupted spans such that the average masked span length is 20 tokens with a noise density of 15%—that is, 15% of tokens in the sequence are masked out, following the specification outlined in the ByT5 paper.
 
-[More Information Needed]
 
-### Results
+#### Optimization
 
-[More Information Needed]
+MrT5 is trained for 5,000 gradient steps over batches of 2^20 tokens (i.e., an encoder sequence length of 1024 with an effective batch size of 1024). We use the AdamW optimizer with an initial learning rate of 1e-4 with linear decay and no warmup.
 
-#### Summary
+To achieve a specific sequence length reduction rate, we use a PI controller with a target deletion ratio of δ=0.5, as described in Section 3.2 of the paper. We also use attention score regularization, as described in Appendix D of the paper.
 
 
-
-## Model Examination [optional]
-
-<!-- Relevant interpretability work for the model goes here -->
-
-[More Information Needed]
-
 ## Environmental Impact
 
-<!-- Total emissions (in grams of CO2eq) and additional considerations, such as electricity usage, go here. Edit the suggested text below accordingly -->
-
-Carbon emissions can be estimated using the [Machine Learning Impact calculator](https://mlco2.github.io/impact#compute) presented in [Lacoste et al. (2019)](https://arxiv.org/abs/1910.09700).
-
-- **Hardware Type:** [More Information Needed]
-- **Hours used:** [More Information Needed]
-- **Cloud Provider:** [More Information Needed]
-- **Compute Region:** [More Information Needed]
-- **Carbon Emitted:** [More Information Needed]
-
-## Technical Specifications [optional]
-
-### Model Architecture and Objective
-
-[More Information Needed]
-
-### Compute Infrastructure
-
-[More Information Needed]
-
-#### Hardware
-
-[More Information Needed]
-
-#### Software
-
-[More Information Needed]
-
-## Citation [optional]
-
-<!-- If there is a paper or blog post introducing the model, the APA and Bibtex information for that should go in this section. -->
-
-**BibTeX:**
-
-[More Information Needed]
-
-**APA:**
-
-[More Information Needed]
-
-## Glossary [optional]
-
-<!-- If relevant, include terms and calculations in this section that can help readers understand the model or model card. -->
-
-[More Information Needed]
-
-## More Information [optional]
-
-[More Information Needed]
-
-## Model Card Authors [optional]
-
-[More Information Needed]
+- **Hardware Type:** NVIDIA A100-SXM4-80GB
+- **GPU Count**: 4
+- **Hours used:** ~73 hours
+- **Cloud Provider:** Stanford NLP Cluster
 
-## Model Card Contact
+## Model Card Authors
 
-[More Information Needed]
+Julie Kallini \
+[email protected]