Bayesian Neural Networks just seem like a failed approach, unfortunately. For one, Bayesian inference and UQ fundamentally depends on the choice of the prior, but this is rarely discussed in the Bayesian NN literature and practice, and is further compounded by how fundamentally hard to interpret and choose these priors are (what is the intuition behind a NN's parameters?). Add to that the fact that the Bayesian infer…
What is 'UQ', I assume some measure of uncertainty over your model outputs?
Bayesian Neural Networks
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Re: Bayesian Neural Networks
#32Bayesian Neural Networks just seem like a failed approach, unfortunately. For one, Bayesian inference and UQ fundamentally depends on the choice of the prior, but this is rarely discussed in the Bayesian NN literature and practice, and is further compounded by how fundamentally hard to interpret and choose these priors are (what is the intuition behind a NN's parameters?). Add to that the fact that the Bayesian infer…
The important thing in bayesian (statistical, ML) modelling in general is the ability to gain in flexibility and do model structures that otherwise would be hard or impossible: latent states, hierarchies, etc.
In bayesian NNs the main advantages would be around uncertainty quantification (UQ) and in finding good optima and partly to avoid overfitting. These do apply in some cases of simple NNs.
Mostly however, especially with larger conventional models (not speaking of normalizing flows and such here), using explicit bayes is not feasible. Instead, people use approximate point estimates with tricks:
(1) UQ has been taken care of by post-calibration. (2) Stochastic gradient actually searches for large posterior masses like a variational approximation would do, so it is kind of bayes. (3) And those priors: using dropout is commonplace, it has a bayesian interpretation, and L2 regularization aka gaussian priors are frequent too.
So bayes is there in practice, just not in a neat, pure form but as a collection of practical hacks.
Re: Bayesian Neural Networks
#33mixture density networks are quite interesting if you want probabilistic estimates of neural. here, your model learns to output and array of gaussian distribution coefficient distributions, and mixture weights.
these weights are specific to individual observations, and trained to maximise likelihood.
Re: Bayesian Neural Networks
#34Re: Bayesian Neural Networks
#35Earlier quoted context omitted.
The Conformal Prediction advocates (especially a certain prominent Twitter account) tend to rehash old frequentist-vs-bayesian arguments with more heated rhetoric than strictly necessary. That fight has been going on for almost a century now. Bayesian counterargument (in caricature form) would be that MLE frequentists just choose an arbitrary (flat) prior, and penalty hyperparameters (common in NN) are a de facto pri…
Yeah, I know the account you are talking about, it really is a bit over the top. It's a shame, I've met a bunch of people who mentioned that they were actually turned away from Conformal Prediction due to them. > But having said that, Conformal Prediction works as advertised for UQ as a wrapper on any point estimating model. If you've got the data for it - and in the ML setting you do - and you don't care about thing…
Re: Bayesian Neural Networks
#36I like Bayesian inference for few-parameter models where I have solid grounds for choosing my priors. For neural networks, I like to ask people "what's your prior for ReLU versus LeakyReLU versus sigmoid?" and I've never gotten a convincing answer.
Re: Bayesian Neural Networks
#37Re: Bayesian Neural Networks
#38Author here! What a surprise. This was an abandoned project from 2019, that we never linked or advertised anywhere as far as I know. Anyways, happy to answer questions.
Re: Bayesian Neural Networks
#39Bayesian Neural Networks just seem like a failed approach, unfortunately. For one, Bayesian inference and UQ fundamentally depends on the choice of the prior, but this is rarely discussed in the Bayesian NN literature and practice, and is further compounded by how fundamentally hard to interpret and choose these priors are (what is the intuition behind a NN's parameters?). Add to that the fact that the Bayesian infer…
> For one, Bayesian inference and UQ fundamentally depends on the choice of the prior, but this is rarely discussed in the Bayesian NN literature and practice, and is further compounded by how fundamentally hard to interpret and choose these priors are (what is the intuition behind a NN's parameters?). I agree that, computationally, it is hard to justify the use of Bayesian methods on large-scale neural networks when…
A Bayesian could try the same thing: try out several priors, and pick the one that performs best in validation. But if you pick your prior based on the data, then the classic theory about “principled quantification of uncertainty” doesn’t apply any more. So you’re left using a computationally unwieldy procedure that doesn’t offer theoretical guarantees.
Re: Bayesian Neural Networks
#40Earlier quoted context omitted.
> For one, Bayesian inference and UQ fundamentally depends on the choice of the prior, but this is rarely discussed in the Bayesian NN literature and practice, and is further compounded by how fundamentally hard to interpret and choose these priors are (what is the intuition behind a NN's parameters?). I agree that, computationally, it is hard to justify the use of Bayesian methods on large-scale neural networks when…
Non-Bayesian NN training does indeed use regularizers that are chosen subjectively —- but they are then tested in validation, and the best-performing regularizer is chosen. Thus the choice is empirical, not subjective. A Bayesian could try the same thing: try out several priors, and pick the one that performs best in validation. But if you pick your prior based on the data, then the classic theory about “principled q…