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Were RNNs all we needed?

arxiv.org

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Re: Were RNNs all we needed?

#93

Earlier quoted context omitted.

> Even if many types of architectures converge to the same loss over time, finding the one that converges the fastest is quite valuable given the cost of running GPU's at scale. This! Not just fastest but with the lowest resources in total. Fully connected neural networks are universal functions. Technically we don’t need anything but a FNN, but memory requirements and speed would be abysmal far beyond the realm of p…

Unless we could build chips in 3D?

Not even then, a truly fully connected network would have super exponential runtime (it would take N^N time to evaluate)

Re: Were RNNs all we needed?

#94
post #20
post #11

It's curse and a blessing that discussion of topics happens in so many different places. I found this comment on Twitter/X interesting: https://x.com/fchollet/status/1841902521717293273 "Interesting work on reviving RNNs. https://arxiv.org/abs/2410.01201 -- in general the fact that there are many recent architectures coming from different directions that roughly match Transformers is proof that architectures aren't f…

What it will come down to is computational efficiencies. We don’t want to retrain once a month - we want to retrain continuously. We don’t want one agent talking to 5 LLMs. We want thousands of LLMs all working in concert.

Sounds like something that has unsustainable energy costs.

Re: Were RNNs all we needed?

#95
post #11

It's curse and a blessing that discussion of topics happens in so many different places. I found this comment on Twitter/X interesting: https://x.com/fchollet/status/1841902521717293273 "Interesting work on reviving RNNs. https://arxiv.org/abs/2410.01201 -- in general the fact that there are many recent architectures coming from different directions that roughly match Transformers is proof that architectures aren't f…

Architecture matters because while deep learning can conceivably fit a curve with a single, huge layer (in theory... Universal approximation theorem), the amount of compute and data needed to get there is prohibitive. Having a good architecture means the theoretical possibility of deep learning finding the right N dimensional curve becomes a practical reality.

Another thing about the architecture is we inherently bias it with the way we structure the data. For instance, take a dataset of (car) traffic patterns. If you only track the date as a feature, you miss that some events follow not just the day-of-year pattern but also holiday patterns. You could learn this with deep learning with enough data, but if we bake it into the dataset, you can build a model on it _much_ simpler and faster.

So, architecture matters. Data/feature representation matters.

Re: Were RNNs all we needed?

#96

Earlier quoted context omitted.

Right. All the squashing is doing is keeping the output of any neuron in a range of below 1. But the entire NN itself (Perceptron ones, which most LLMs are) is still completely using nothing but linearity to store all the knowledge from the training process. All the weights are just an 'm' in the basic line equation 'y=m*x+b'. The entire training process does nothing but adjust a bunch of slopes of a bunch of lines.…

The non linearities are fundamental. Without them, any arbitrarily deep NN is equivalent to a shallow NN (easily computable, as GP was saying), and we know those can't even solve the XOR problem. > nothing but linearity No, if you have non linearities, the NN itself is not linear. The non linearities are not there primarily to keep the outputs in a given range, though that's important, too.

> The non linearities are not there primarily to keep the outputs in a given range

Precisely what the `Activation Function` does is to squash an output into a range (normally below one, like tanh). That's the only non-linearity I'm aware of. What other non-linearities are there?

All the training does is adjust linear weights tho, like I said. All the training is doing is adjusting the slopes of lines.

Re: Were RNNs all we needed?

#97
post #93

Earlier quoted context omitted.

Unless we could build chips in 3D?

Not even then, a truly fully connected network would have super exponential runtime (it would take N^N time to evaluate)

We need quantum computing there. I remember seeing a recent article about quantum processes in the brain. If that’s true, QC may be the missing part.

Re: Were RNNs all we needed?

#98
post #47

My feeling is that the answer is "no", in the sense that these RNNs wouldn't be able to universally replace Transformers in LLMs, even though they might be good enough in some cases and beat them in others. Here's why. A user of an LLM might give the model some long text and then say "Translate this into German please". A Transformer can look back at its whole history. But what is an RNN to do? While the length of it…

> the amount of information the model retains about it is bounded by whatever is in its hidden state This is no different than a transformer, which, after all, is bound by a finite state, just organized in a different manner.

> This is no different than a transformer, which, after all, is bound by a finite state, just organized in a different manner.

It's not just a matter of organizing things differently. Suppose your network dimension and sequence length are both X.

Then your memory usage (per layer) will be O(X^2), while your training update cost will be O(X^3). That's for both Transformers and RNNs.

However, at the end of the sequence, a Transformer layer can look back see O(X^2) numbers, while an RNN can only see O(X) numbers.

Re: Were RNNs all we needed?

#99

Earlier quoted context omitted.

The non linearities are fundamental. Without them, any arbitrarily deep NN is equivalent to a shallow NN (easily computable, as GP was saying), and we know those can't even solve the XOR problem. > nothing but linearity No, if you have non linearities, the NN itself is not linear. The non linearities are not there primarily to keep the outputs in a given range, though that's important, too.

> The non linearities are not there primarily to keep the outputs in a given range Precisely what the `Activation Function` does is to squash an output into a range (normally below one, like tanh). That's the only non-linearity I'm aware of. What other non-linearities are there? All the training does is adjust linear weights tho, like I said. All the training is doing is adjusting the slopes of lines.

> squash an output into a range

This isn't the primary purpose of the activation function, and in fact it's not even necessary. For example see ReLU (probably the most common activation function), leaky ReLU, or for a sillier example: https://youtu.be/Ae9EKCyI1xU?si=KgjhMrOsFEVo2yCe

Re: Were RNNs all we needed?

#100
post #20

Earlier quoted context omitted.

What it will come down to is computational efficiencies. We don’t want to retrain once a month - we want to retrain continuously. We don’t want one agent talking to 5 LLMs. We want thousands of LLMs all working in concert.

Sounds like something that has unsustainable energy costs.

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