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Show HN: Predictive text using only 13kb of JavaScript. no LLM

207 points| adamkochanowicz | 2 years ago |adamgrant.info

39 comments

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janalsncm|2 years ago

Pretty cool, a js implementation of n-grams!

What is amazing to me is this: imagine that English only had 10,000 words. For each of those 10,000 words there’s 100 valid subsequent words. So there’s 1 million valid bigrams. Now if you want trigrams that takes you to 100 million, and for 4-grams it’ll be 10 billion. Just for that, you’d need 14 bytes per word and gigabytes of storage.

LLMs typically have context windows in the hundreds if not thousands. (Back in my day GPT2 had a context window of 1024 and we called that an LLM. And we liked it.) So it’s kind of amazing that a model that can fit on a flash drive can make reasonable next token prediction on the whole internet and with a context size that can fit a whole book.

10000truths|2 years ago

That's because a vast majority of the set of grammatically correct n-grams are not actually useful in practical language. "Colorless green ideas sleep furiously" is valid English, but it is semantically nonsense.

cchance|2 years ago

I mean ... technically Gemini 1.5 has 10 million context which just pushes the insanity further lol

throwaway4aday|2 years ago

Nice work! I built something similar years ago and I did compile the probabilities based on a corpus of text (public domain books) in an attempt to produce writing in the style of various authors. The results were actually quite similar to the output of nanoGPT[0]. It was very unoptimized and everything was kept in memory. I also knew nothing about embeddings at the time and only a little about NLP techniques that would certainly have helped. Using a graph database would have probably been better than the datastructure I came up with at the time. You should look into stuff like Datalog, Tries[1], and N-Triples[2] for more inspiration.

Your idea of splitting the probabilities based on whether you're starting the sentence or finishing it is interesting but you might be able to benefit from an approach that creates a "window" of text you can use for lookup, using an LCS[3] algorithm could do that. There's probably a lot of optimization you could do based on the probabilities of different sequences, I think this was the fundamental thing I was exploring in my project.

Seeing this has inspired me further to consider working on that project again at some point.

[0] https://github.com/karpathy/nanoGPT

[1] https://en.wikipedia.org/wiki/Trie

[2] https://en.wikipedia.org/wiki/N-Triples

[3] https://en.wikipedia.org/wiki/Longest_common_subsequence

sodimel|2 years ago

This is cool. I don't want a 1GB+ download and an entire LLM running on my machine (or worse, on someone else machine) to find words.

What I really want is some simple predictive text engine to make writing in English easier (because its not my first language), helping me find more complex words that I don't use because I don't know them well enough.

mromanuk|2 years ago

I've developed a neural network model for text correction, prediction, and autocompletion, specifically optimized for one of my iOS keyboard apps. The model is compact, at only 32MB, allowing for swift loading times. It predicts the next word based on the last four to five words, demonstrating robustness against errors, typos, and making minor grammar corrections.

The goal was to mimic the functionality of the stock iOS keyboard. This approach also opens up the possibility of training (or fine-tuning) the model with specialized vocabularies for various professional fields, such as law, medicine, and engineering, to predict, correct, and autocomplete domain-specific terms. I'm exploring whether this addresses a genuine need or is a solution in search of a problem.

Additionally, I'm considering integrating a comprehensive grammar correction feature directly into the keyboard. While there are existing apps with this capability, they rely on online APIs. My aim is to offer a self-contained, local model as an alternative.

pseudo_meta|2 years ago

Seeing that you use Obsidian: Have you thought about turning that into an Obsidian plugin that offers the predictions as editor suggestions?

adzm|2 years ago

So this is basically a Markov chain right?

hidelooktropic|2 years ago

I don't think so. It's basically just traversing nested arrays and picking a random member on each level.

underscoring|2 years ago

Nice work!

> If it can do this in 13kb, it makes me wonder what it could do with more bytes.

Maybe I misunderstand, but is this not just the first baby steps of an LLM written in JS? "what it could do with more bytes" is surely "GPT2 in javascript"?

refulgentis|2 years ago

Author had LLM help them make a tree of words, and the algo choose which node we're at and offers children as completions. It's clever and cute but, not even close to an LLM.

zerojames|2 years ago

Another day, another story on HN that will have me down a rabbit hole (yesterday's was a three-hour tangent into ternary bit compression after the Microsoft paper) :D

Your project is delightful -- thank you for sharing. I have explored this realm a bit before [0] [1], but in Python. The tool I made was for personal use, but streaming every keystroke through a network connection added a lot of unnecessary latency.

I used word surprisals (entropy) to calculate the most likely candidates, and gave a boost to words from my own writing (thus, the predictive engine was "fine-tuned" on my writing). The result is a dictionary of words with their probabilities of use. This can be applied to bigrams, too. Your project has me thinking: how could that be pruned, massively, to create the smallest possible structure. Your engine feels like the answer.

My use case is technical writing: you know what you want to say, including long words you have to repeat over again, but you want a quicker way of typing.

[0]: https://jamesg.blog/2023/12/15/auto-write/

[1]: https://github.com/capjamesg/autowrite

amne|2 years ago

"What if we go to a place where there is no way"

Barely got 1 or 2 suggestions while typing that. Am I holding it wrong?

neom|2 years ago

I tried for "once in a while we all get sad" and it got exactly zero.

SamBam|2 years ago

What's the data corpus? I'm very surprised that the words "Be," "Of," and "And" are among the 25 most common first words of sentences.

hidelooktropic|2 years ago

I think the LLM that helped coauthor the tree hallucinated these suggestions. Probably better to actually train it on some text.

tagueis|2 years ago

What tool are you using to view dictionary.js in your screenshot?

schnuri|2 years ago

Cool thing!

But: The demo is not usable for me on my mobile device, the keyboard is missing a tab key.

valval|2 years ago

What's the point? I tested it out for around 10 seconds and noticed that it's completely useless.

awayto|2 years ago

For those moments when you just don't know what (5 phrases) to say?

qingcharles|2 years ago

I'm not sure why you're getting downvoted, the actual results were pretty subpar in my experience.

The idea is good, though.

k__|2 years ago

What does that mean no LLM?

Markov chains have been a thing for a long time and predictive text was used before LLMs.

hidelooktropic|2 years ago

It means it doesn't use a large language model. I don't think this is a claim to have been the first to do it.