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ramity

169 karma · joined July 26, 2022

https://github.com/ramity "It's closed source until it isn't."

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ramity··on In Defense of Pure 16-Bit Floating-Point Neural Networks
The precision used should match the requirements of the dataset, the training process, and the available compute. There are practical uses to 16-Bit FP training.

"Our findings demonstrate that pure 16-bit floating-point neural networks can achieve similar or even better performance than their mixed-precision and 32-bit counterparts." This is a very deceptive statement. Take 100 initialization states and train a FP16 vs a FP32 network, and you'll find FP32 will have an accuracy advantage. It's certainly possible to conclude this if a small sample of networks are trained. This paper goes on to state, "Lowering the precision of real numbers used for the neural network’s weights to fixed-point, as shown in [11], leads to a significant decrease in accuracy.", while later concluding, "we have shown that pure 16-bit networks can perform on par with, if not better than, mixed-precision and 32-bit networks in various image classification tasks." The results certainly do, but that doesn't really give an accurate evaluation of what's really going on here. A FP64 network can fall into a local minima and be outperformed by a PF16 network, but is it correct to say the FP16 network is better. I'm getting a lot of mixed signals.

I feel like, "significant implications" is quite a stretch.

A few concerns: Besides figure 3, other results do not provide side-by-side test vs validation accuracy to attempt demonstrate the network is not overfit, and the only mention of normalization was the custom batch normalization operation.

This may more be a rant about the current state of ML, but in a perfect world, we wouldn't use GPUs/would enforce deterministic calculations, results would be replicable, we'd train hundreds if not thousands of networks to draw conclusions from, we'd better understand how to visualize network accuracies and overfitting, and all datasets would be free of bias and accurately generalize the problem attempting to be modelled. We can dream.

ramity··on Ask HN: I am a full stack developer, where do I start learning for AI
I didn't feel like the parent comment was worth downvoting, and I share most of your perspectives. I agree that AI safety is ripe for contributions, but I'd personally argue AI safety is a very wide and encompassing topic that requires a good foundational understanding of AI. In the context of ML, AI safety is applicable to the entire process; from dataset creation, training, utilization, etc.

In regards to your comment on AI safety being "underutilized", my thoughts are that it's just simply difficult to do. Let's put aside all the difficulties of training, verification, etc and just look at the data problem.

If you wish to make certain that your system meets some given AI safety standard, then you must somehow prove two things: the data the model ingests when deployed will always return the correct response and that the dataset composes/generalizes the data the model will ingest when deployed. For simple problems, this may be doable. For complex, multidimensional problems wherein the dataset must only hope to generalize the complex input it will encounter during deployment, this may be next to infeasible.

I'm definitely getting off topic here, but bias of all kinds exists even human operated systems eg car. I can't say I've ever seen a firetruck stopped on the highway before, but perhaps I'd know what it is and how to avoid it. If a dataset does not contain that event, how can we be certain an AI system would understand? I'm not sure if it's possible to create a dataset that will be without bias in the case of complex problems, but I'm certain we can create one that's performant at driving than I. So the questions of "how safe is enough?", then proving/demonstrating that safety, and more are particularly open topics. I enjoy making the point that there is the lack of rigorous standards for humans, as we hold computers to far higher standards, but ML models probabilistically navigate decisions similar to us.

I'm sure this reply could extend further, but this and more are my defense of why I believe AI safety is a wide topic. None of the above should dissuade beginners from exploring the subtopic, but it's certainly not something you'd be able to learn first without strong, foundational context.

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