Transformers Explained Visually

aray07 303 points 47 comments September 21, 2026
poloclub.github.io · View on Hacker News

Discussion Highlights (15 comments)

tanseydavid

Nice work. I really appreciate this tool for enhancing my limited understanding the mechanism(s) behind attention and LLMs.

jwpapi

Damn that page took down my Chromebook, never happened before..

utopcell

Great site, intuitive description. I also found [1] very useful in the past. [1] https://bbycroft.net/llm

esseph

This is not at all what I was hoping for. Expected a lot more Unicron.

andblac

Nicely done. For me the most fascinating thing about attention heads is the place where Attention matrix is already computed and is getting multiplied by Value vector. It behaves exactly like pushing Value vector through Dense layer of ordinary network where Attention matrix forms weights of that layer. So attention head is trained to construct this small single layer network dynamically during inference from Key and Query. And that's the point. That's rarely underlined in explanations of LLMs architecture and for me it's quite amazing that it works so well. This mechanism easy to observe in this particular visualization if you click through it.

E-Reverance

I get that this is for explaining GPT-2, but I really hope laymen don't use it as an example of how modern models work (ex. absolute positional encoding is no longer used) edit: I know that it mentions its not modern, but these kinds of details have major implications in terms of the representations a model can learn, which is in many ways the most important part!

bilsbie

I never understood the thinking behind the separate key query value matrixes? What are they doing exactly?

robrenaud

Regarding the temperature explanation: > "Instead of picking the highest-probability token, we can use different selection strategies to balance safety and creativity in the generated text". Safety is definitely the wrong word here. Temperature 0 generated text actually has a weird "lack of surprise" character that makes it seem artificial. [1] > "high-probability texts can be dull or repetitive. Humans use language as a means of communicating information, aiming to do so in a simultaneously efficient and error-minimizing manner; in fact, psycholinguistics research suggests humans choose each word in a string with this subconscious goal in mind." I'd completely drop the dropout explanation. It's just not part of the modern recipe anymore, AFAICT. As for the ambitious goal of explaining transformers with a single interactive visualization, I just have a hard time imagining a person is going to newly understand both word embeddings (word2vec blew my mind in 2014) and also gain an understanding of attention. I am making my own visualizations for a presentation on "Full Bandwidth Transformers"[2] that I am giving tomorrow at the Deep Learning Study Group (SF) (on zoom for the non-locals)[3]. It's not meant to be stand alone/context free, but I'd love some feedback. https://rrenaud.github.io/fullbandwidth_transformer_viz/ [1] https://arxiv.org/abs/2202.00666 [2] https://arxiv.org/abs/2608.08888 [3] https://www.meetup.com/deep-learning-sf/events/316601593/

throw0101a

As someone with an EE degree (though a sysadmin), this use of the term "transformer" is constantly confusing. :) (Also "cryto" for cryptocurrency rather than cryptography.)

jasonjmcghee

For the uninitiated, I can't recommend enough, The Illustrated Transformer: https://jalammar.github.io/illustrated-transformer/

ftumminello

Why did the inner EE in me think this was going to be a power transformer lol

dionian

Great UI and it was very helpful to me as a newcomer

noncovalence

Hm, I wonder why my laptop is suddenly pulling about 5 fps while I'm just browsing HN? The nefarious "2.2 GB RAM usage within 10 seconds" tab open in the background:

unixhero

Can it do Jev too?

est

It seem that everyone is getting into details of how transformers work, but I am more interested in why other setups didn't work. Or is it?

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