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Harnessing the Universal Geometry of Embeddings

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Re: Harnessing the Universal Geometry of Embeddings

#21

Hi HN, I'm Jack, the last author of this paper. It feels good to release this, the fruit of a two-year quest to "align" two vector spaces without any paired data. It's fun to look back a bit and note that at least two people told me this wasn't possible: 1. An MIT professor who works on similar geometry alignment problems didn't want to work on this with me because he was certain we would need at least a little bit o…

I am a curious amateur, so I may say something dumb. but: Suppose you take a number of smaller embedding models, and one more advanced embedding model. Suppose for a document, you convert each model's embeddings to their universal embedding representation and examine the universal embedding spaces.

On a per document basis, would the universal embeddings of the smaller models (less performant) cluster around the better model's universal embedding space, in a way suggestive that they are each targeting the 'true' embedding space, but with additional error/noise?

If so, can averaging the universal embeddings from a collection of smaller models effectively approximate the universal embedding space of the stronger model? Could you then use your "averaged universal embeddings" as a target to train a new embedding model?

Re: Harnessing the Universal Geometry of Embeddings

#22

Hi HN, I'm Jack, the last author of this paper. It feels good to release this, the fruit of a two-year quest to "align" two vector spaces without any paired data. It's fun to look back a bit and note that at least two people told me this wasn't possible: 1. An MIT professor who works on similar geometry alignment problems didn't want to work on this with me because he was certain we would need at least a little bit o…

I hate to be "reviewer 2", but:

I used to work on what your paper calls "unsupervised transport", that is machine translation between two languages without alignment data. You note that this field has existed since ~2016 and you provide a number of references, but you only dedicate ~4 lines of text to this branch of research. There's no comparison about why your technique is different to this prior work or why the prior algorithms can't be applied to the output of modern LLMs.

Naively, I would expect off-the-shelf embedding alignment algorithms (like https://github.com/artetxem/vecmap> and https://github.com/facebookresearch/fastText/tree/main/align...>, neither of which are cited or compared against) to work quite well on this problem. So I'm curious if they don't or why they don't.

I can imagine there is lots of room for improvements around implicit regularization in the algorithms. Specifically, these algorithms were designed with word2vec output in mind (typically 300 dimensional vectors with 200000 observations), but your problem has higher dimensional vectors with fewer observations and so would likely require different hyperparameter tuning. IIRC, there's no explicit regularization in these methods, but hyperparameters like stepsize/stepcount can implicitly add L2 regularization, which you probably need for your application.

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PS.

I *strongly dislike* your name of vec2vec. You aren't the first/only algorithm for taking vectors as input and getting vectors as output, and you have no right to claim such a general title.

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PPS.

I believe there is a minor typo with footnote 1. The note is "Our code is available on GitHub." but it is attached to the sentence "In practice, it is unrealistic to expect that such a database be available."

Re: Harnessing the Universal Geometry of Embeddings

#23

Hi HN, I'm Jack, the last author of this paper. It feels good to release this, the fruit of a two-year quest to "align" two vector spaces without any paired data. It's fun to look back a bit and note that at least two people told me this wasn't possible: 1. An MIT professor who works on similar geometry alignment problems didn't want to work on this with me because he was certain we would need at least a little bit o…

I hate to be "reviewer 2", but: I used to work on what your paper calls "unsupervised transport", that is machine translation between two languages without alignment data. You note that this field has existed since ~2016 and you provide a number of references, but you only dedicate ~4 lines of text to this branch of research. There's no comparison about why your technique is different to this prior work or why the pr…

Naming things is hard. Noting the two alternative approaches that you referenced are called "vecmap" and "alignment" which "aren't the first/only algorithm for ... and you have no right to claim such a general title" could easily apply there as well.

Re: Harnessing the Universal Geometry of Embeddings

#25

Hi HN, I'm Jack, the last author of this paper. It feels good to release this, the fruit of a two-year quest to "align" two vector spaces without any paired data. It's fun to look back a bit and note that at least two people told me this wasn't possible: 1. An MIT professor who works on similar geometry alignment problems didn't want to work on this with me because he was certain we would need at least a little bit o…

I hate to be "reviewer 2", but: I used to work on what your paper calls "unsupervised transport", that is machine translation between two languages without alignment data. You note that this field has existed since ~2016 and you provide a number of references, but you only dedicate ~4 lines of text to this branch of research. There's no comparison about why your technique is different to this prior work or why the pr…

Hey, I appreciate the perspective. We definitely should cite both those papers, and will do so in the next version of our draft. There are a lot of papers in this area, and they're all a few years old now, so you might understand how we missed two of them.

We tested all of the methods in the Python Optimal Transport package (https://pythonot.github.io/) and reported the max in most of our tables. So some of this is covered. A lot of these methods also require a seed dictionary, which we don't have in our case. That said, you're welcome to take any number of these tools and plug them into our codebase; the results would definitely be interesting, although we can expect the adversarial methods still work best, as they do in the problem settings you mention.

As for the name – the paper you recommend is called 'vecmap' which seems equally general, doesn't it? Google shows me there are others who have developed their own 'vec2vec'. There is a lot of repetition in AI these days, so collisions happen.

Re: Harnessing the Universal Geometry of Embeddings

#26

Hi HN, I'm Jack, the last author of this paper. It feels good to release this, the fruit of a two-year quest to "align" two vector spaces without any paired data. It's fun to look back a bit and note that at least two people told me this wasn't possible: 1. An MIT professor who works on similar geometry alignment problems didn't want to work on this with me because he was certain we would need at least a little bit o…

Does this result imply that if we had a LLM trained on a very large volume of only English data, and one trained only on a very large volume of data in another language, your technique could be used to translate between the two languages? Pretty cool. If we somehow came across a huge volume of text in an alien language, your technique could potentially translate their language into ours (although maybe the same could be achieved just by training a single LLM on both languages?).

Re: Harnessing the Universal Geometry of Embeddings

#27

Hi HN, I'm Jack, the last author of this paper. It feels good to release this, the fruit of a two-year quest to "align" two vector spaces without any paired data. It's fun to look back a bit and note that at least two people told me this wasn't possible: 1. An MIT professor who works on similar geometry alignment problems didn't want to work on this with me because he was certain we would need at least a little bit o…

Don't you mean "John" instead of "Jack"? :)

Re: Harnessing the Universal Geometry of Embeddings

#29
post #10

Hi HN, I'm Jack, the last author of this paper. It feels good to release this, the fruit of a two-year quest to "align" two vector spaces without any paired data. It's fun to look back a bit and note that at least two people told me this wasn't possible: 1. An MIT professor who works on similar geometry alignment problems didn't want to work on this with me because he was certain we would need at least a little bit o…

I must admit reading the abstract made me think to myself that I should read the paper in skeptical mode. Does this extend to being able to analytically determine which concepts are encodable in one embedding but not another? An embedding from a deft tiny stories LLM presumably cannot encode concepts about RNA replication. Assuming that is true. If you can detect when you are trying to put a square peg into a round h…

I read a lot of AI papers on arxiv, and it's been a while since I read one where the first line of the abstract had me scoffing and done.

> We introduce the FIRST method for translating text embeddings from one vector space to another without any paired data

(emphasis mine)

Nope. I'm not gonna go a literature search for you right now and find the references, but this is certainly not the first attempt to do unsupervised alignment of embeddings, text or otherwise. People were doing this back in ~2016.

Re: Harnessing the Universal Geometry of Embeddings

#30
post #20

Earlier quoted context omitted.

Very fair! > Does this extend to being able to analytically determine which concepts are encodable in one embedding but not another? An embedding from a deft tiny stories LLM presumably cannot encode concepts about RNA replication. Yeah, this is a great point. We're mostly building off of this prior work on the Platonic Representation Hypothesis ( https://arxiv.org/abs/2405.07987 ). I think our findings go-so-far as…

>So I don't think your tinystories example qualifies for the PRH, since it's not enough data and it's not representative of the whole Internet. And RNA data is (I would guess) something very different altogether. My thought there was that you'd be comparing tinystories to a model that trained on the entire internet. The RNA related information would be a subset of the second representation that has no comparable enco…

As I read the paper, you would be able to detect it in a couple of ways

1. possibly high loss where the models don't have compatible embedding concepts 2. given a sufficient "sample" of vectors from each space, projecting them to the same backbone would show clusters where they have mismatched concepts

It's not obvious to me how you'd use either of those to tweak the vector space of one to not represent some concept, though.

But if you just wanted to make an embedding that is unable to represent some concept, presumably you could already do that by training disjoin "unrepresentable concepts" to a single point.

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