A Dive Into Multihead Attention, Self-Attention and Cross-Attention

[@qwertypwnown]

You make great videos with great explanations! I can listen to you all day

[@isaiasprestes9759]

This paper is amazing! Thank you very much for making this video. Quite good!

[@davefaulkner6302]

Regarding Multi-headed attention: it wasn't until you listed the dimensions of the output heads that it became clear that you are splitting the input by the embedding dimension, d, across the different heads. This should have been made more explicit in your explanation. Regardless, I was looking for the answer to this question of how the input was split across the heads so thank you for this detailed explanation of how the multi-headed mechanism works.

[@jacobyoung2045]

Thanks, your comment made it clearer for me.

[@chrisogonas]

Very well illustrated! Thanks

[@PyMLstudio]

Glad you liked it!

[@maryammohseni4507]

great video!tnx

[@gusbakker]

Thanks! Really nice explanation

[@MrDelord39]

Thank you for this video :)

[@xxxiu13]

This is a great explanation.

[@milanvasilic4510]

Greate explanation, thx :). So the headnumber just tells me how many weight matrices i have for K, Q and V?

[@angelineamber]

Hi, thanks for the amazing video. One question. I get d, q,k,v but didn't get the denotation W.

[@Lesoleil370]

Thanks, so w is a learnable matrix to get q, k, and v. So to get q, we use q=w_q x, and similarly , for k and v: q=W_q x k=W_k x v=W_v x

[@angelineamber]

@@Lesoleil370 thank you!

[@mehdimohsenimahani4150]

great great 👍💯

[@PyMLstudio]

Thanks 🙏🏻

[@gigglygeekgal]

Great Explanation :)

[@quentinparrenin2484]

great video ! Really enjoyed the explaination in a simple way specially for the cross attention. Any plan to explain some other concept aside some python ? Would love it

[@PyMLstudio]

Thanks for the comment. Yes, my plan is to first cover transformers , then I’ll also cover more general machine learning and deep learning concepts as well, and some of them with Python implementation

[@me-ou8rf]

Can you suggest some materials that deal with how transformer can be applied to time series database like EEG ?

[@NaveenKumar-vn7vx]

thank you

[@paktv858]

what is the difference between self attention and multi head self attention? is both are same just instead of single attention multi head attention use multi heads?

[@temanangka3820]

6:00 Does each attention head only process part of embeded token? Example: Say, there is 100 token and 2 attention heads. Does each head only process 50 tokens. ?? If yes, then how can we make sure each head can understand whole context of sentence, while it only consumes half of sentence?

[@PyMLstudio]

That’s a great question The multihead attention splits the feature dimension not the sequence dimension. So that way, each head is able to see entire sequence, but working on a smaller feature-size. Example : input is 100 token and each embedding vector is 256 dimensional . Then with 8 heads , each head will process tensors of size 100x16

[@temanangka3820]

@@PyMLstudio understood... Great explanation.. Thank you, Bro...

[@just4visit]

where do the W come from?

[@PyMLstudio]

Good question! These W matrices are learnable parameters of the model. They could be initialized randomly if we build a transformer from scratch, and gradually updated and learned through back-propagation.

[@harshaldharpure9921]

How to do the cross attention mechanism if we have a three feature x,y, rag with size of x.shape torch.Size([8, 768]) y.shape torch.Size([8, 512]) rag.feature torch.Size([8, 768])

[@PyMLstudio]

So, let's assume query=y, key=x, and value=rag for our explanation, but remember, you can adjust this configuration depending on your specific needs. Given these tensors, our first step is to ensure that the dimensions of the query, key, and value match for the attention mechanism to work properly. Since y has a different dimension (512) compared to x and rag (768), we need to project y to match the 768-dimension space of x and rag: query_projector = Linear(512, 768) query_projected = query_projector(query) ## --> 8x768 With this projection, all three tensors (query_projected, key=x, value=rag) now share the same dimensionality (8x768), making them compatible for the multi-head attention, where each head involves dot-product between query_projected and keys, followed by Softmax and multiplying by the values. Remember that the assignment of x/y/rag to query/key/value can change depending on your use case and where these tensors come from. I hope this answers your question.

[@harshaldharpure9921]

Thanks a lot sir @@PyMLstudio

[@Yaz71023]

When you find people who makes science easy and engoyable 🫡

[@isaiasprestes9759]

This paper is amazing! Thank you very much for making this video. Quite good!