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--- |
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language: |
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- en |
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tags: |
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- pytorch |
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- causal-lm |
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- pythia |
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license: apache-2.0 |
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datasets: |
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- the_pile |
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--- |
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The *Pythia Scaling Suite* is a collection of models developed to facilitate |
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interpretability research. It contains two sets of eight models of sizes |
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70M, 160M, 410M, 1B, 1.4B, 2.8B, 6.9B, and 12B. For each size, there are two |
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models: one trained on the Pile, and one trained on the Pile after the dataset |
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has been globally deduplicated. All 8 model sizes are trained on the exact |
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same data, in the exact same order. All Pythia models are available |
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[on Hugging Face](https://huggingface.co/EleutherAI). |
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The Pythia model suite was deliberately designed to promote scientific |
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research on large language models, especially interpretability research. |
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Despite not centering downstream performance as a design goal, we find the |
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models match or exceed the performance of similar and same-sized models, |
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such as those in the OPT and GPT-Neo suites. |
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Please note that all models in the *Pythia* suite were renamed in January |
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2023. For clarity, a <a href="#naming-convention-and-parameter-count">table |
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comparing the old and new names</a> is provided in this model card, together |
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with exact model parameter counts. |
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## Pythia-2.8B |
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### Model Details |
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- Developed by: [EleutherAI](http://eleuther.ai) |
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- Model type: Transformer-based Language Model |
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- Language: English |
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- Learn more: [Pythia's GitHub repository](https://github.com/EleutherAI/pythia) |
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for training procedure, config files, and details on how to use. |
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- Library: [GPT-NeoX](https://github.com/EleutherAI/gpt-neox) |
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- License: Apache 2.0 |
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- Contact: to ask questions about this model, join the [EleutherAI |
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Discord](https://discord.gg/zBGx3azzUn), and post them in `#release-discussion`. |
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Please read the existing *Pythia* documentation before asking about it in the |
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EleutherAI Discord. For general correspondence: [contact@eleuther. |
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ai](mailto:[email protected]). |
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<figure> |
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| Pythia model | Non-Embedding Params | Layers | Model Dim | Heads | Batch Size | Learning Rate | Equivalent Models | |
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| -----------: | -------------------: | :----: | :-------: | :---: | :--------: | :-------------------: | :--------------------: | |
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| 70M | 18,915,328 | 6 | 512 | 8 | 2M | 1.0 x 10<sup>-3</sup> | — | |
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| 160M | 85,056,000 | 12 | 768 | 12 | 4M | 6.0 x 10<sup>-4</sup> | GPT-Neo 125M, OPT-125M | |
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| 410M | 302,311,424 | 24 | 1024 | 16 | 4M | 3.0 x 10<sup>-4</sup> | OPT-350M | |
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| 1.0B | 805,736,448 | 16 | 2048 | 8 | 2M | 3.0 x 10<sup>-4</sup> | — | |
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| 1.4B | 1,208,602,624 | 24 | 2048 | 16 | 4M | 2.0 x 10<sup>-4</sup> | GPT-Neo 1.3B, OPT-1.3B | |
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| 2.8B | 2,517,652,480 | 32 | 2560 | 32 | 2M | 1.6 x 10<sup>-4</sup> | GPT-Neo 2.7B, OPT-2.7B | |
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| 6.9B | 6,444,163,072 | 32 | 4096 | 32 | 2M | 1.2 x 10<sup>-4</sup> | OPT-6.7B | |
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| 12B | 11,327,027,200 | 36 | 5120 | 40 | 2M | 1.2 x 10<sup>-4</sup> | — | |
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<figcaption>Engineering details for the <i>Pythia Suite</i>. Deduped and |
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non-deduped models of a given size have the same hyperparameters. “Equivalent” |
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models have <b>exactly</b> the same architecture, and the same number of |
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non-embedding parameters.</figcaption> |
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</figure> |
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### Uses and Limitations |
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#### Intended Use |
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The primary intended use of Pythia is research on the behavior, functionality, |
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and limitations of large language models. This suite is intended to provide |
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a controlled setting for performing scientific experiments. To enable the |
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study of how language models change over the course of training, we provide |
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143 evenly spaced intermediate checkpoints per model. These checkpoints are |
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hosted on Hugging Face as branches. Note that branch `143000` corresponds |
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exactly to the model checkpoint on the `main` branch of each model. |
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You may also further fine-tune and adapt Pythia-2.8B for deployment, |
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as long as your use is in accordance with the Apache 2.0 license. Pythia |
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models work with the Hugging Face [Transformers |
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Library](https://huggingface.co/docs/transformers/index). If you decide to use |
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pre-trained Pythia-2.8B as a basis for your fine-tuned model, please |
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conduct your own risk and bias assessment. |
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#### Out-of-scope use |
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The Pythia Suite is **not** intended for deployment. It is not a in itself |
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a product and cannot be used for human-facing interactions. |
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Pythia models are English-language only, and are not suitable for translation |
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or generating text in other languages. |
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Pythia-2.8B has not been fine-tuned for downstream contexts in which |
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language models are commonly deployed, such as writing genre prose, |
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or commercial chatbots. This means Pythia-2.8B will **not** |
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respond to a given prompt the way a product like ChatGPT does. This is because, |
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unlike this model, ChatGPT was fine-tuned using methods such as Reinforcement |
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Learning from Human Feedback (RLHF) to better “understand” human instructions. |
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#### Limitations and biases |
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The core functionality of a large language model is to take a string of text |
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and predict the next token. The token deemed statistically most likely by the |
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model need not produce the most “accurate” text. Never rely on |
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Pythia-2.8B to produce factually accurate output. |
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This model was trained on [the Pile](https://pile.eleuther.ai/), a dataset |
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known to contain profanity and texts that are lewd or otherwise offensive. |
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See [Section 6 of the Pile paper](https://arxiv.org/abs/2101.00027) for a |
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discussion of documented biases with regards to gender, religion, and race. |
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Pythia-2.8B may produce socially unacceptable or undesirable text, *even if* |
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the prompt itself does not include anything explicitly offensive. |
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If you plan on using text generated through, for example, the Hosted Inference |
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API, we recommend having a human curate the outputs of this language model |
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before presenting it to other people. Please inform your audience that the |
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text was generated by Pythia-2.8B. |
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### Quickstart |
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Pythia models can be loaded and used via the following code, demonstrated here |
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for the third `pythia-70m-deduped` checkpoint: |
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```python |
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from transformers import GPTNeoXForCausalLM, AutoTokenizer |
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model = GPTNeoXForCausalLM.from_pretrained( |
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"EleutherAI/pythia-70m-deduped", |
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revision="step3000", |
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cache_dir="./pythia-70m-deduped/step3000", |
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) |
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tokenizer = AutoTokenizer.from_pretrained( |
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"EleutherAI/pythia-70m-deduped", |
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revision="step3000", |
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cache_dir="./pythia-70m-deduped/step3000", |
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) |
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inputs = tokenizer("Hello, I am", return_tensors="pt") |
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tokens = model.generate(**inputs) |
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tokenizer.decode(tokens[0]) |
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``` |
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Revision/branch `step143000` corresponds exactly to the model checkpoint on |
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the `main` branch of each model. |
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For more information on how to use all Pythia models, see [documentation on |
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GitHub](https://github.com/EleutherAI/pythia). |
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### Training |
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#### Training data |
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[The Pile](https://pile.eleuther.ai/) is a 825GiB general-purpose dataset in |
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English. It was created by EleutherAI specifically for training large language |
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models. It contains texts from 22 diverse sources, roughly broken down into |
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five categories: academic writing (e.g. arXiv), internet (e.g. CommonCrawl), |
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prose (e.g. Project Gutenberg), dialogue (e.g. YouTube subtitles), and |
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miscellaneous (e.g. GitHub, Enron Emails). See [the Pile |
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paper](https://arxiv.org/abs/2101.00027) for a breakdown of all data sources, |
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methodology, and a discussion of ethical implications. Consult [the |
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datasheet](https://arxiv.org/abs/2201.07311) for more detailed documentation |
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about the Pile and its component datasets. The Pile can be downloaded from |
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the [official website](https://pile.eleuther.ai/), or from a [community |
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mirror](https://the-eye.eu/public/AI/pile/). |
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The Pile was **not** deduplicated before being used to train Pythia-2.8B. |
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#### Training procedure |
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Pythia uses the same tokenizer as [GPT-NeoX- |
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20B](https://huggingface.co/EleutherAI/gpt-neox-20b). |
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All models were trained on the exact same data, in the exact same order. Each |
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model saw 299,892,736,000 tokens during training, and 143 checkpoints for each |
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model are saved every 2,097,152,000 tokens, spaced evenly throughout training. |
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This corresponds to training for just under 1 epoch on the Pile for |
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non-deduplicated models, and about 1.5 epochs on the deduplicated Pile. |
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All *Pythia* models trained for the equivalent of 143000 steps at a batch size |
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of 2,097,152 tokens. Two batch sizes were used: 2M and 4M. Models with a batch |
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size of 4M tokens listed were originally trained for 71500 steps instead, with |
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checkpoints every 500 steps. The checkpoints on Hugging Face are renamed for |
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consistency with all 2M batch models, so `step1000` is the first checkpoint |
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for `pythia-1.4b` that was saved (corresponding to step 500 in training), and |
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`step1000` is likewise the first `pythia-6.9b` checkpoint that was saved |
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(corresponding to 1000 “actual” steps). |
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See [GitHub](https://github.com/EleutherAI/pythia) for more details on training |
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procedure, including [how to reproduce |
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it](https://github.com/EleutherAI/pythia/blob/main/README.md#reproducing-training). |
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### Evaluations |
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All 16 *Pythia* models were evaluated using the [LM Evaluation |
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Harness](https://github.com/EleutherAI/lm-evaluation-harness). You can access |
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the results by model and step at `results/json/*` in the [GitHub |
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repository](https://github.com/EleutherAI/pythia/tree/main/results/json). |
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February 2023 note: select evaluations and comparison with OPT and BLOOM |
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models will be added here at a later date. |
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### Naming convention and parameter count |
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*Pythia* models were renamed in January 2023. It is possible that the old |
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naming convention still persists in some documentation by accident. The |
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current naming convention (70M, 160M, etc.) is based on total parameter count. |
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<figure style="width:32em"> |
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| current Pythia suffix | old suffix | total params | non-embedding params | |
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| --------------------: | ---------: | -------------: | -------------------: | |
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| 70M | 19M | 70,426,624 | 18,915,328 | |
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| 160M | 125M | 162,322,944 | 85,056,000 | |
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| 410M | 350M | 405,334,016 | 302,311,424 | |
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| 1B | 800M | 1,011,781,632 | 805,736,448 | |
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| 1.4B | 1.3B | 1,414,647,808 | 1,208,602,624 | |
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| 2.8B | 2.7B | 2,775,208,960 | 2,517,652,480 | |
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| 6.9B | 6.7B | 6,857,302,016 | 6,444,163,072 | |
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| 12B | 13B | 11,846,072,320 | 11,327,027,200 | |
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</figure> |
