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Jay Alammar

Verified account Cohere

@JayAlammar

Machine Learning Researcher and writer newsletter.languagemodels.co. O'Reilly Author LLM-book.com. LLM Builder @Cohere.
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Jay Alammar Verified account @JayAlammar
We're ecstatic to bring you "How Transformer LLMs Work" -- a free course with ~90 minutes of video, code, and crisp visuals and animations that explain the modern Transformer architecture, tokenizers, embeddings, and mixture-of-expert models.

@MaartenGr and I have developed a lot of the visual language over the last several years (tens of thousands of iterations for hundreds of figures) for the book. But to have an opportunity to collaborate with the legendary @AndrewYNg, we took them to the next level with animations and a concise narrative meant to enable technical learners to pick up an ML paper and understand the architecture description.

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Andrew Ng Verified account @AndrewYNg Feb 5, 2025
Announcing How Transformer LLMs Work, created with @JayAlammar and @MaartenGr, co-authors of the beautifully illustrated book, “Hands-On Large Language Models.”

This course offers a deep dive into the inner workings of the transformer architecture that powers large language models (LLMs).

The transformer architecture revolutionized generative AI; in fact, the "GPT" in ChatGPT stands for "Generative Pre-Trained Transformer." Originally introduced in the Google Brain team's groundbreaking 2017 paper "Attention Is All You Need," by Vaswani and others, transformers were a highly scalable model for machine translation tasks. Variants of this architecture now power today’s LLMs such as those from OpenAI, Google, Meta, Cohere, Anthropic and DeepSeek.

In this course, you’ll learn in detail how LLMs process text. You'll also work through code examples that illustrate that transformer's individual components.

In details, you’ll learn:
- How the representation of language has evolved, from Bag-of-Words to Word2Vec embeddings to the transformer architecture that captures a word's meanings taking into account the context of other words in the input.
- How inputs are broken down into tokens before they are sent to the language model.
- The details of a transformer's main stages: Tokenization and embedding, the stack of transformer blocks, and the language model head.
- The inner workings of the transformer block, including attention, which calculates relevance scores, and the feedforward layer, which incorporates stored information learned in training.
- How cached calculations make transformers faster.
- Some of the most recent ideas in the latest models such as Mixture-of-Experts (MoE) which uses multiple sub-models and a router on each layer to improve the quality of LLMs.

By the end of this course, you’ll have a deep understanding of how LLMs actually process text and be able to read through papers describing the latest models and understand the details.

Gaining this intuition will improve your approach to building LLM applications.

Please sign up here: deeplearning.ai/short-courses/…
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Jay Alammar Verified account @JayAlammar
How ML research shifted between 2025 and 2026:
Beautiful Neurips research map from @askalphaxiv using @cohere Embed 5 embeddings!
alphaXiv Verified account @askalphaxiv Oct 14
Where is research attention moving according to arXiv papers?

We mapped 10,000 of the most-read papers on alphaXiv, weighted by readership, to see how interest shifted from 2025 to 2026. Here’s what we found:

1) Traditional RL post-training is getting less attention. As the focus moves beyond math and reasoning to longer agent tasks, compute demands put this research out of reach for many teams

2) Harnesses, agent systems, memory and distillation are gaining reading share, offering other ways to improve what models can do

3) Interest is also growing in robotics and world models, bringing AI into the physical world
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Jay Alammar Verified account @JayAlammar
Figure 1-20 is the most important figure out of the 330+ in An Illustrated Guide to AI Agents.

1- It shows what today's LLM-based AI agents are composed of, including their user and environment loops.

2- It is also therefore a table of contents for Part 1: Agent Fundamentals, showing where each of the key components is explained in details.

Read it here:
Amazon: amazon.com/Illustrated-Gu…
O'Reilly: learning.oreilly.com/library/view/a…
PDF e-book: ebooks.com/en-ca/book/347…
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