Embeddings Are Underrated

You can't visualize it but you can certainly compute the euclidean distance. Tools like UMAP can be used to drop the dimensionality as well.

Note you don't see arXiv papers where somebody feeds in 1000 male gendered words into a word embedding and gets 950 correct female gendered words. Statistically it does better than chance, but word embeddings don't do very well.

In

https://nlp.stanford.edu/projects/glove/

there are a number of graphs where they have about N=20 points that seem to fall in "the right place" but there are a lot of dimensions involved and with 50 dimensions to play with you can always find a projection that makes the 20 points fall exactly where you want them fall. If you try experiments with N>100 words you go endlessly in circles and produce the kind of inconclusively negative results that people don't publish.

The BERT-like and other transformer embeddings far outperform word vectors because they can take into account the context of the word. For instance you can't really build a "part of speech" classifier that can tell you "red" is an adjective because it is also a noun, but give it the context and you can.

In the context of full text search, bringing in synonyms is a mixed bag because a word might have 2 or 3 meanings and the the irrelevant synonyms are... irrelevant and will bring in irrelevant documents. Modern embeddings that recognize context not only bring in synonyms but the will suppress usages of the word with different meanings, something the IR community has tried to figure out for about 50 years.

Oh yes, this makes a lot of sense, thank you for the "nit" (which doesn't feel like a nit to me, it feels like an important conceptual correction). When I was writing the post I definitely paused at that part, knowing that something was off about describing the model as having a dimension that maps to gender. As you said, since the models are general-purpose and work so well in so many domains, there's no way that there's a 1-to-1 correspondence between concepts and dimensions.

I think your comment is also clicking for me now because I previously did not really understand how cosine similarity worked, but then watched videos like this and understand it better now: https://youtu.be/e9U0QAFbfLI

I will eventually update the post to correct this inaccuracy, thank you for improving my own wetware's conceptual model of embeddings

>nearly orthogonal dimensions within n dimensional space

nit within a nit: I believe you intended to write "nearly orthogonal directions within n dimensional space" which is important as you are distinguishing direction from dimension in your post.

Thanks for the write-up!

I’m curious how you found the quality of the results? This gets into evals which ML folks love, but even just with “vibes” do the results eyeball as reasonable to you?

It would be great to semantically search through literature with embeddings. At least one person I know if is trying to generate a vector database of all arxiv papers.

The big problem I see is attribution and citations. An embedding is just a vector. It doesn't contain any citation back to the source material or modification date or certificate of authenticity. So when using embeddings in RAG, they only serve to link back to a particular page of source material.

Using embeddings as links doesn't dramatically change the way citation and attribution are handled in technical writing. You still end up citing a whole paper or a page of a paper.

I think GraphRAG [1] is a more useful thing to build on for technical literature. There's ways to use graphs to cite a particular concept of a particular page of an academic paper. And for the 'citations' to act as bidirectional links between new and old scientific discourse. But I digress

[1] https://microsoft.github.io/graphrag/

> were any direct applications to tech writers discussed in this article

No, it was supposed to be a teaser post followed up by more posts and projects exploring the different applications of embeddings in technical writing (TW). But alas, life happened, and I'm now a proud new papa with a 3-month old baby :D

I do have other projects and embeddings-related posts in the pipeline. Suffice to say, embeddings can help us make progress on all 3 of the "intractable" challengs of TW mentioned here: https://technicalwriting.dev/strategy/challenges.html

Semantic search and classification and clustering. For the first, there is a substantial breakthrough in IR every 10 years or so you take what you can get. (I got so depressed reading TREC proceedings which seemed to prove that "every obvious idea to improve search relevance doesn't work" and it wasn't until I found a summary of the first ten years that I learned that the first ten years had turned up one useful result, BM2.5)

As for classification, it is highly practical to put a text through an embedding and then run the embedding through a classical ML algorithm out of

https://scikit-learn.org/stable/supervised_learning.html

This works so consistently that I'm considering not packing in a bag-of-words classifier in a text classification library I'm working on. People who hold court on Huggingface forums tends to believe you can do better with fine-tuned BERT, and I'd agree you can do better with that, but training time is 100x and maybe you won't.

20 years ago you could make bag-of-word vectors and put them through a clustering algorithm

https://scikit-learn.org/stable/modules/clustering.html

and it worked but you got awful results. With embeddings you can use a very simple and fast algorithm like

https://scikit-learn.org/stable/modules/clustering.html#k-me...

and get great clusters.

I'd disagree with the bit that it takes "a lot of linear algebra" to find nearby vectors, it can be done with a dot product so I'd say it is "a little linear algebra"

I built an rss aggregator with semantic search using embeddings. The main usage was being able to categorise based on any randomly created category. So you could have arbitrary categories

https://github.com/aws-samples/rss-aggregator-using-cohere-e...

Unfortunately I no longer work at AWS so the infrastructure that was running it is down.

How would you approach using them in a specialized discipline (think technical jargon, acronyms etc) where traning a model from scratch is practically impossible because everyone (customers, solution providers) fiercely guards their data?

A generic embedding model does not have enough specificity to cluster the specialized terms or "code names" of specific entities (these differ across orgs but represent the same sets of concepts within the domain). A more specific model cannot be trained because the data is not available.

Quite the conundrum!

A case related to that is "more like this" which in my mind breaks down into two forks:

(1) Sometimes your query is a short document. Say you wanted to know if there were any patents similar to something you invented. You'd give a professional patent searcher a paragraph or a few paragraphs describing the invention, you can give a "semantic search engine" the paragraph -- I helped build one that did about as well as the professional using embeddings before this was cool.

(2) Even Salton's early works on IR talked about "relevance feedback" where you'd mark some documents in your results as relevant, some as irrelevant. With bag-of-words this doesn't really work well (it can take 1000 samples for a bag-of-words classifier to "wake up") but works much better with embeddings.

The thing is that embeddings are "hunchy" and not really the right data structure to represent things like "people who are between 5 feet and 6 feet tall and have been on more than 1000 airplane flights in their life" (knowledge graph/database sorts of queries) or "the thread that links the work of Derrida and Badiou" (could be spelled out logically in some particular framework but doing that in general seems practically intractable)

In my benchmarks for a service which is now running in production, hybrid search based on both keywords and embeddings performed the best. Sometimes you need exact keyword matches; other times, synonyms are more useful. Hybrid search combines both sets of results into a single, unified set. OpenSearch has built-in support for this approach.

they're both useful

search is an active "I'm looking for X"

related articles is a passive "hey thanks for reading this article, you might also like Y"