The Weekly Kaitchup #10

Zephyr 7B - LongLLMLingua - gte-tiny - Mistral 7B paper - OpenWebMath

Benjamin Marie

Oct 13, 2023

Hi Everyone,

In this edition of The Weekly Kaitchup:

Zephyr 7B: first 7B LLM to outperform Llama 2 70B
Small and accurate embeddings with gte-tiny
LongLLMLingua: prompt compression for longer contexts
The publication of the paper describing Mistral 7B
A new dataset containing all the math documents from Common Crawl

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Zephyr 7B: First 7B LLM to Outperform Llama 2 70B

Hugging Face also makes LLMs. Their new model, Zephyr 7B, has only 7 billion parameters but outperforms Llama 2 70B, a 70 billion parameter model, in writing, STEM, extraction, coding, and roleplay. It seems a bit behind for reasoning and math but, given that it’s a model 10 times smaller, that’s still quite impressive.

The base model is Mistral 7B. Hugging Face has fine-tuned it with supervised fine-tuning (SFT) on the UltraChat dataset. Then, to align the model with RLHF, they didn’t use the standard PPO but Direct Preference Optimization (DPO) instead. DPO is much simpler than PPO. For DPO, they used the dataset UltraFeedBack.

Direct Preference Optimization: Your Language Model is Secretly a Reward Model (Rafailov et al., 2023)

Hugging Face has released Zephyr 7B with a license cc-by-nc 4.0 (we can’t use it for commercial purposes).

If you are interested in training your own RLHF model, have a look at my previous article using DeepSpeed Chat with PPO:

Train Instruct LLMs On Your GPU with DeepSpeed Chat — Step #3: Reinforcement Learning with Human Feedback

September 21, 2023

Read full story

gte-tiny Embeddings

If you are interested in small and accurate embeddings, have a look at gte-tiny. They are available on the Hugging Face Hub:

TaylorAI/gte-tiny

This is a sentence-transformer model that performs as well as OpenAI embeddings.

You can use this model to map sentences, paragraphs, and documents, to a 384-dimension space.

LongLLMLingua: Prompt Compression for Longer Contexts

I hope someone has already started to write a survey on techniques extending LLMs’ context. There are so many that it’s challenging to keep track of all the advances. Many research papers share similar ideas but we lack clear comparisons of all techniques to understand which one is the best for a given scenario.

This work by Microsoft doesn’t explicitly increase the context length but compresses it by dividing by 4 (on average) its number of tokens.

LongLLMLingua: Accelerating and Enhancing LLMs in Long Context Scenarios via Prompt Compression (Jiang et al., 2023)

Since the prompts are compressed, we can feed longer prompts to LLMs. A side effect is that the latency of the LLM, i.e., the time we have to wait before it generates the first token, is also reduced since the context is smaller and thus faster to process.

Microsoft released an implementation of LongLLMLingua on GitHub (MIT license).

Mistral 7B Paper

Mistral AI published the paper describing their Mistral 7B. You can find it on arXiv:

Mistral 7B (Jiang et al., 2023)

Mistral 7B is a very good (and fast) LLM outperforming larger ones. However, you won’t find why in this paper... They didn’t disclose anything new from what they have already published in their blog post or the Mistral 7B model card.

I assume that Mistral 7B performs very well thanks to very good training data, probably generated by larger models, similar to what Microsoft did to train phi-1.5. But this is really just an assumption since the paper doesn’t mention anything about the training data.