Bamba: An open-source LLM that crosses a transformer with an SSM

(research.ibm.com)

158 points | by shallow-mind 13 hours ago ago

52 comments

  • adt 10 hours ago

    https://lifearchitect.ai/models-table/

    Love those GPQA scores hovering around 5% when chance (on 4-way multi-choice) would have got them 25%!

    • dudeinhawaii 4 hours ago

      or.. A stopped clock is right twice a day; a mis-prompted LLM is wrong 19 times out of 20—but only because we handed it the wrong instruction sheet.

      Procedural error in testing perhaps? I'm not familiar with the methodology for GPQA.

    • montebicyclelo 8 hours ago

      So could do better than chance by excluding the option it's picked?

    • gryfft 9 hours ago

      A stopped clock is right twice a day, but a running clock set to the wrong time is always wrong.

      • nthingtohide 6 minutes ago

        > a running clock set to the wrong time is always wrong.

        Could be right within 15 min accuracy in the appropriate timezone. And such a mechanism can be corrected for in the postprocessing step.

      • cwt137 6 hours ago

        Not always true! Your statement is only true when the running clock's speed is the same as time. Thus, regular time and the clock's time will never meet.

        If the clock is running faster than regular time, it will at point catch up to regular time and thus be correct for a split second. If the clock is slower than regular time, regular time will catch up to the clock and the clock will be right for a split second.

        • nathan_douglas 3 hours ago

          If the clock is running backwards at very high speed, it would be right infinitely many times but the proportion of the time that it is right would approach some finite constant.

        • actionfromafar 5 hours ago

          If we are being pedantic, running clocks never run exactly the same as time. So they'll be right (very) much more seldom than the stopped clock, which is right twice a day.

      • parrit 8 hours ago

        The RMS of wrongness of the running clock is probably lower.

  • bushbaba 3 hours ago

    Wonder if the name is inspired by my favorite snack, bamba. The best are the hazelnut bamba.

    Btw bamba if given to kids at a young age can drastically reduce the chance of peanut allergies

    • visarga 2 hours ago

      Let me show you the etymology of Bamba:

      SSM (state space model) -> SSSM (structured state space model) -> (it's like a snake ssss...) Mamba -> Bamba

      • zaptrem a minute ago

        Where does the B come from?

  • mh- 13 hours ago

    SSM = state-space model, for the unfamiliar.

    https://en.wikipedia.org/wiki/State-space_representation

  • mentalgear 9 hours ago

    > chose to make just about everything associated with Bamba open-source — the training recipes, the data, the data loader IBM designed for largescale distributed training, and a quantization framework aimed at shaving storage and inferencing costs.

  • jmward01 11 hours ago

    This type of architecture is definitely the future. Unlimited attn is a dead end. As a human you don't need to scan an entire book just to guess what the next word will be and LLMs shouldn't need that either.

    • og_kalu an hour ago

      Humans can re-attend to material whenever necessary (i.e you can just re-read a book, re-watch a documentary etc when you feel you have missed crucial context) so it's not the end of the world. These SSMs or modern RNNs can't and if crucial context has been discarded by the end of the query then well too bad. Transformers are of course always re-attending so not an issue for them either. Until that issue is resolved, i don't think attention will be going anywhere.

    • quantadev 10 hours ago

      Not be contrarian, but if the next word prediction happens to be someone's name or a place or something discussed multiple places in the book then often, yes, a knowledge of the full plot of the book is "required" just to predict the next word, as you get to the middle or end of a book.

      For example you could never fill in the last chapter of any good book without having knowledge of every previous chapter. Not highly detailed knowledge, but still knowledge.

      • parrit 8 hours ago

        What an LLM does is stuff it all into short term memory. Humans dump the first pages into long term memory and "make sense" of it. Humans have a massive context window because of this (and sheer brain size and efficiency).

        • boroboro4 3 hours ago

          We don’t put things into long term memory after we read it. We usually put it after night of sleep. I personally think that context (and kv cache correspondingly) in the models are akin to our short term memory, while training process (and actual weights) are to our long term memory. And we can’t be sure our short term memory doesn’t work in a way of matching the current context towards currently stored short term memory. From this perspective transformers are enough and just fine.

          • parrit 3 hours ago

            So if you now hide my original comment and try to recall what I said, do you know it word for word (and are thinking if every word, e.g. did I use one or 2 spaces somewhere as that would change tokens) or do you have a rough concept of what I said?

            OTOH if you had to remember a phone number to write it down, how does that differ?

            • boroboro4 2 hours ago

              I think in a way it makes transformers superior to humans, their short term memory is much more powerful =) Supporting extra long contexts also make transformers super human. Because, again, human's short term memory is exactly this - short term. And much shorter than millions of tokens we expect from models nowadays.

              As for SSMs - I think they compress model memory state way too much. Mixed global/local attention layers do just as well. And sparse/block attention seems like a way forward much more (https://arxiv.org/abs/2502.11089).

          • quantadev 34 minutes ago

            Human memory works completely different. It's not information stored in neurons, or being computed. My theory is that Eternalism ('Block Universe' is the other term) is real and that all memory is accomplished by the fact that your brain remains Quantum Entangled with all past and future "copies" of itself.

            You know what "copies" means if you understand Eternalism. Each moment in the past "still" exists, and always exists. Probably about 50% of the best Physicists believe 'crazy' concepts like this (and multiverse, etc), even though it sounds crazy to uneducated people. The only thing that differentiates us is which crazy idea each of us buys into.

            I believe all high negentropy systems can interact with their own future/past via the long causality chain going in both directions. This is how non-brain cell based intelligences work too (like Fungi and Plant life). Memory and Consciousness is essentially a retro-causal wave resonance across the entire causality chain of complex systems. We know for sure consciousness is far more correlated to waves than it is to synaptic actions. Neurons and synapses just carry signals. All the memory in consciousness is in the wave domain, as a secondary emergent effect of neuron charge flows.

  • roger_ 7 hours ago

    Never got how mamba models work in multiple dimensions and non-causally.

  • joshjob42 11 hours ago

    For some reason this link isn't loading, but it's on https://archive.ph/Ks0xt

  • aantix 10 hours ago

    Where's the code?

  • cubefox 8 hours ago

    Another recent transformer/SSM hybrid is "M1", with a more than 3x claimed inference speed-up compared to equivalent transformers: https://arxiv.org/pdf/2504.10449

    IBM is claiming at least a 2x inference speed-up with Bamba. Both groups say that future SSM optimizations to vLLM would lead to further inference speed improvement.

  • gitroom 4 hours ago

    the name bamba is killing me lol, all i can see is the snack now

  • jwilber 10 hours ago

    LLM/state space models have been popular for some years now, see: https://arxiv.org/abs/2212.14052

    More recently, hybrid architectures that utilize attention plus other operators are gaining traction.

    See https://arxiv.org/abs/2503.01868

  • antirez 12 hours ago

    Dear IBM name pickers: "Bamba", in Italian, means cocaine.

    • _davide_ 9 hours ago

      When I read the title 'IBM crossed a transformer with an SSM and got ‘Bamba’' I laughed so hard I woke up my kid

    • alex7o 11 hours ago

      It's just a mamba (https://github.com/state-spaces/mamba) but with a transformer. Idk where the B comes from.

    • iddan 11 hours ago

      And in Heberw it's the name of a snack made of peanut-butter-flavored puffed maize https://en.wikipedia.org/wiki/Bamba_(snack)

      • kridsdale1 10 hours ago

        I imported these to America to feed my infant. Data shows the prevalence of peanut allergies lines up with when AAP guidelines started recommending that babies do NOT eat peanut. Israel never went along with this and thus has the lowest rates of allergies in the world.

        • itayd 7 minutes ago

          You actually don't need to self import these. Usually Safeway (is it only a west coast thing?) always have these stocked in the Kosher section.

        • arijun 10 hours ago

          I think the difference in allergy rates between UK and Israeli Ashkenazi Jews (10x higher in UK Jews!) [1] is strong evidence for that.

          Also, they sell Bamba at Trader Joe’s now.

          [1] https://www.jacionline.org/article/S0091-6749(08)01698-9/ful...

        • cycomanic 9 hours ago

          Latest research does strongly suggest that introducing small amounts of common allergens (peanuts, shellfish,milk products...) as early as possible does significantly reduce risk for allergies later. Many early childhood organisations already recommend this. Official health recommendations are often slow to catch up (often for good reasons, but introducing peanuts etc. early is already officially recommended in quite a few countries (Australia, NZ, Sweden for example AFAIK). Not all health professionals are always up to date either though.

      • bonzini 11 hours ago

        As an Italian who has tried (only) the Israeli Bamba, I can certify that it is pretty addictive.

    • rdtsc 9 hours ago

      So someone can get fired for picking IBM after all! Or get a bonus, depending on the organization...

    • amitport 12 hours ago
    • folgoris 7 hours ago

      A very funny and friendly way to say "cocaine" among italians. I'm struggling to read it seriously.

    • fb03 5 hours ago

      and in Portuguese, it means "flimsy". What a great name.

    • rzzzt 12 hours ago

      Para bailar La Bamba / Se necesita una poca de gracia

    • dismalaf 7 hours ago

      Seems like a good fit.

    • vienzo 9 hours ago

      And in Lithuanian it's a navel

    • lenerdenator 7 hours ago

      about time they did something to liven things up at big blue

    • francasso 12 hours ago

      SSMs never stop

    • beanjuiceII 10 hours ago

      i mean that sounds good to me

  • samanator 13 hours ago

    Yummy