Asymmetric Quantization: Near-Lossless Retrieval with 97% Storage Reduction (mixedbread.com)
109 points by breadislove 4 days ago
Zagreus2142 a day ago
``` We evaluated several precision pairings across our internal retrieval benchmark suite. Scores are NDCG@10 averaged across the suite, scaled to 0–100. NDCG@10 (Normalized Discounted Cumulative Gain at rank 10) measures how well the top 10 results are ordered against the ideal ranking, rewarding relevant documents more when they appear higher, with 100 being a perfect ranking. The full-precision baseline averages 90.26. Int8 query against binary documents averages 89.65, a 0.61 point drop, while reducing document-vector storage by 32x ```
Saying "Near lossless" to mean 90% accurate retrieval of saved vectors is simply a lie. Lossy-ness is binary, not something you can paper over with getting close enough. And 90% is not close. Sure, LLMs are all about gradient descent on noisy data sets so I guess this is acceptable in this field but that terminology usage still bothered me
kittoes a day ago
I don't believe that's what they were saying at all though. The claim appears to be that it's near lossless relative to their own baseline that uses float. Which I'd grant, since a 32x storage reduction for 0.61% loss in quality is a reasonable trade off when you've already decided to accept that ~90% is "good enough".
coldtea 9 hours ago
>Saying "Near lossless" to mean 90% accurate retrieval of saved vectors is simply a lie. Lossy-ness is binary, not something you can paper over with getting close enough.
Lossy-ness is a binary, "near lossness" however is still valid (and is not the same as saying lossless).
How else, if not by comparing to "lossness" (whether with a more abstract qualitative term like "near" or with some distance or error measurement) do you report the level of fidelity to non-lossy results?
Depends on the context, but even in abstract for whatever domain, 90% sounds pretty close if we're talking about a linear level of degradation corresponding to each X% level.
In this case if this is calculated on a lossless baseline that's itself close to 90% - it's distance from it, it doesn't represent distance from some pure 100% perfect retrieval. So ~90% vs ~89% is very close to lossless capability.
seritools a day ago
near lossless refers to being 89.65/90.26 = 99.32% of baseline, i'm pretty sure.
breadislove a day ago
yes exactly.
theropost a day ago
Yeah, what bugs me about stuff like that is like they spend all this time and then they output several or minimal real testing to prove the theory It's like you're building your model to And just because it takes a long time to compute and do the testing, you'd rather publish your article and then try to get credit on something that hasn't really been proven. Look, prove your results. Study it. Ruggedize it. Make sure it works. Then, show us.
ttoinou a day ago
Ask a SOTA LLM when Newton was born without any access to internet : the answer is Lossless for our shared culture understanding of this question. Not Near-lossless, lossless. Ask the same LLM when YOU were born, the answer is just wrong for almost anyone in the world, not lossy. Between the two there is a whole new field of Lossyness to study.
90% depends entirely on what the measure means here, do you understand what "Normalized Discounted Cumulative Gain at rank 10" means to the set of data that we are comparing ?
Sometimes coming up with new codecs (compressors decompressors) means coming up with new ways to interpret artifacts of the real world. And this is exactly why LLM are so powerful and they are like a giant Lossy (but Near-Lossless for various use cases) ZIP file / Database of the whole knowledge of the training data.
Nobody is trying to manipulate you here, humanity just has to find new explanations for complex topics.
Lossy-ness is binary
Lossless is binary in pure information theory. to quote my other comment :Lossless is objective for information theory. To get from the real world to digital world you need an analog to digital converter, this process is by definition lossy. We are interested in the real world, and information is pure but never represents exactly reality. Lossyness is baked into our problem statement here.
Using terms like near lossless means we think we are very close to reality for what we’re trying to do
elil17 a day ago
I would love to see real examples of what reduced quality means in practice. Are you able to recover a document from the vector in a human readable format? If so, what sort of changes come up?
I could imagine a scenario where differences tend to be more substantive than you'd expect because of how less frequent words with fine distinctions in meaning - the very words that make the document special - may be embedded in the vector space.
yorwba a day ago
Most of the fine distinctions are already lost when a document is processed through a pile of linear algebra to turn it into a fixed-size list of floating-point numbers, as you can see from the NDCG@10. Vector search is not a tool for fine distinctions. It's a tool for reducing a large pile of documents to a smaller selection of candidates, which you can then check individually with some more expensive method.
breadislove a day ago
The ndcg loss is minimal 90.26 -> 89.65. This means it maintains most of the quality.
breadislove a day ago
this is the reason why we report ndcg and not recall. ndcg respects fine grained details so you get the an overview of how much details you are trading off since it would hurt the ranking.
purple-leafy a day ago
Hey breadislove; amazing article, I’ll be sending mixedbread an email in the morning that may interest you (email will be <5-characters>@pm.me)
I have also been working in compression and performance engineering, and managed to get a 99+% compression unlock versus conventional approaches (100+KB down to 1KB) in the scenario of 30 minute massive multiplayer game replays for a “game+engine” I’m developing
I think there’s a synergy between these 2 concepts I’d love to chat some more
palinnilap a day ago
Any way I can read about this or the use case? I have a hobby interest
purple-leafy a day ago
Yes soon I’ll be launching my game and engine, and will have a blog post - just keep an eye on Show HN over the following week
undefined a day ago
breadislove a day ago
to which email did you send it? can u send it to support please?
purple-leafy a day ago
Sent to the support email with the subject line “Hackernews …”
derrickquinn a day ago
Asymmetry is clever. FWIW, this is very similar to the strategy employed by BitNet models (i.e., int8 activations with binary or ternary weights); I suspect retrieval is a little more amenable to this approach.
In principle, binary x binary should be pretty fast since it just requires bitwise XNOR and popcount/reduction, but in practice it's slow unless you've really optimized it. And, as stated in the article, you'd still be losing a lot of accuracy that way.
kaizenite a day ago
To people smarter than me, how impressive and/or revolutionary is this?
alfiedotwtf a day ago
If you squint hard enough, it sounds like their storage layer is a bloom filter
rq1 a day ago
The Pi compression algorithm is better.
luma a day ago
Doubtful. The problem with the pi idea is that you need to include the offset, which will likely be as long as or longer than your data.
nathan_compton a day ago
" A single document produces more then one embedding, depending on the complexity of the document it can produce hundreds or thousands of vectors."
That typo up there is kind of endearing in the AI slop era.
HenryMulligan a day ago
Not seeing a typo in your quote. Can you point it out?
thatspartan a day ago
I think they're referring to "then" vs "than"
breadislove a day ago
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undefined a day ago
TradingReality 3 days ago
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Ameo a day ago
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mwigdahl a day ago
Unfortunately as cost reduction trends to 100%, it comes along with an intrinsic high-pass sarcasm filter.
peheje a day ago
Reminds me of 'Learning to be me' by Greg Egan
throwaway2027 a day ago
You would obviously be trading storage for compute and time to retrieve the storage.
throwaw12 a day ago
100% reduction is impossible for something which should work, because -100% means it is now 0
neonstatic a day ago
They were clearly being sarcastic
functionmouse a day ago
there is no such thing as "near lossless"
ttoinou a day ago
There is, after you define what you’re ready to loose and understand the lossy space. That’s how we came up with mobile cellphones, audio and video codecs etc. Literally powering all modern devices we use.
greenleafone7 a day ago
So then ... "lossy"
magicalhippo 13 hours ago
tancop a day ago
undefined a day ago
functionmouse a day ago
Actually, all of those things are considered "lossy".
ttoinou a day ago
breadislove 19 hours ago
yes, your are right. what heading would you have taken here?