Live data from Hacker News

Exploring Weight Agnostic Neural Networks

ai.googleblog.com

11–20 of 67 posts

Re: Exploring Weight Agnostic Neural Networks

#11
post #6

Unpopular quote from my image and video processing professor - “The only problem with machine learning is that the machine does the learning and you don’t.” While I understand that is missing a lot of nuance, it has stuck with me over the past few years as I feel like I am missing out on the cool machine learning work going on out there. There is a ton of learning about calculus, probability, and statistics when doin…

I'd highly recommended watching this podcast interview between Lex Fridman and the creator of fast.ai, released yesterday: https://youtu.be/4CTDdxfSXF0

He covers a lot of relevant and interesting topics, including how he tries make it less of a black box when designing their courses, and also how it has the potential to confer increased rather than decreased insight into what's going on in a dataset.

I don't personally know much about ML, but I think even though there will still be probably an opaque aspect in many cases for a while to come, immense value will still be continually gleaned, as long as people are aware of the limitations. If you accept something is a black box and don't oversell it, a black box is better than no box.

All of our own brains are far more of a black box than any deep learning model, in many capacities. But we still use it daily for meat-machine learning, to great success, and can still tune the parameters a bit to improve outcomes, even if we very often don't really understand exactly what we're tuning or why it seems to cause certain effects for some brains (or why it doesn't have those effects for other brains). Consciousness may be the biggest black box of them all, but here we are all talking and making nearly non-stop use of it.

I agree it's very important to try our hardest to reach a deeper understanding, but it's kind of like psychiatry vs. neuroscience, or experimental quantum physicists who "shut up and calculate" vs. theoretical quantum physicists who actually want to know what's really going on here at the most fundamental level beyond the useful black box of quantum behavior. While we're trying to solve the hard problems of deep understanding, we can make practical use of what we have in the meantime. We need both kinds of fields and people.

If future AI architectures and ideas lead to some degree of convergence with a biological brain, I wonder if the black box problem might become amplified. Maybe one part of the solution is to not use the brain as the model to aspire to, and to eventually seek out alternative avenues to higher, and eventually general, intelligence? (Or maybe I'm completely talking out of my ass, because I'm not at all a researcher or practitioner. I'd appreciate any input from experts.)

Re: Exploring Weight Agnostic Neural Networks

#12
How is it different than pruning a neural network?

It seems you could train the weights of a state of the art NN, then quantizite it, then prune it. It will remove some weights of the NN, then all the remaining weights are set to the same value. Isn't training then pruning more efficient than using an architecture search algorithm ?

Re: Exploring Weight Agnostic Neural Networks

#13
post #9

how is this different from boring old evolutionary algorithms? In my opinion the big breakthrough that enabled optimization and machine learning was the discovery of reverse mode automatic differentiation, since the space or family of all possible decision-functions is high dimensional, while the goal (survival, reproduction) is low dimensional. Unless I see a mathematical proof that evolutionary algorithms are as ef…

In the related work section of their paper they mention that WANNs are related to genetic programming [1], a subfield of evolutionary algorithms. Genetic programming is quite a powerful tool. IIRC, a few years ago, a researcher evolved expressions to model the dynamics of a double pendulum based only on measured data. To his surprise he found that the expressions were the Lagrangian of the system. [1] https://en.wiki…

but a double pendulum isn't complicated at all!

how many floats are there? 2 lengths, 2 initial angles, a 2-dimensional velocity, a mass, and a gravitational field strength? thats like 8 floats...

Re: Exploring Weight Agnostic Neural Networks

#15
post #2

I wrote a series of Markov chat simulators as a teenager. Often I used a simpler algorithm which ignored the probability weight (all out-links, once learned, given equal probability). These version performed subjectively as well as, if not better, than the versions which tracked the weight of links. I'm not surprised therefore that weight agnostic neural networks can work, too.

I think it may not be a great comparison. N-grams (of words) of human speech/writing are way more deterministic than the kinds of things ML usually tries to tackle, I think. If you write the word "because", then "of", "the", or some pronoun are all extremely safe bets for the next word, regardless of their recorded probabilities. I imagine you could also totally randomize the probabilities and not see any issues.

But I'm no expert and hardly even an amateur, so maybe it is a similar kind of thing here with ML. And I know randomized optimization is a big thing in ML, though I'm not sure to what extent that could be analogized with randomizing Markov model probabilities.

Re: Exploring Weight Agnostic Neural Networks

#16
post #6

Unpopular quote from my image and video processing professor - “The only problem with machine learning is that the machine does the learning and you don’t.” While I understand that is missing a lot of nuance, it has stuck with me over the past few years as I feel like I am missing out on the cool machine learning work going on out there. There is a ton of learning about calculus, probability, and statistics when doin…

"what is exciting to you about your work?" Seeing the black boxes solve problems I know I could not solve manually. If you go into industry, expect to be spending the vast majority of your time wrangling data, integrating the black boxes into other software, and apologizing repeatedly to managers because you have no idea how long it will take to make your black box work, if it ever does. Trying to make plans around AI based software is an exercise in futility.

Re: Exploring Weight Agnostic Neural Networks

#17

how is this different from boring old evolutionary algorithms? In my opinion the big breakthrough that enabled optimization and machine learning was the discovery of reverse mode automatic differentiation, since the space or family of all possible decision-functions is high dimensional, while the goal (survival, reproduction) is low dimensional. Unless I see a mathematical proof that evolutionary algorithms are as ef…

>Unless I see a mathematical proof that evolutionary algorithms are as efficient as RM AD, I see little future in it, and apparently neither did biology since it decided to create brains. In the biological context the complexity is shifted away from the actual selection algorithm and onto the "scoring function." Although the filter of reproduction is relatively simple [1], the reason why the organism was fit and coul…

with efficiency I meant computational efficiency:

consider the task of computing a gradient at a point p0 = in an N-dimensional space.

the naive approach was for a long time: compute the value of the score at p0, then for each coordinate compute the score for the same point but shifted a delta in the direction of that coordinate, i.e. the i-th component is computed as:

component_i = (score( ) - score (p0))/delta

thats N+1 evaluations or trials of the score to compute the final gradient

notice how reminescent this is of natural selection: the average of the last generation p0 is used to generate ~N trials, which then result in the average of the next generation shifting somewhat.

compare reverse mode automatic differentiation to calculate a gradient: one forward pass of the computation with one backward pass...

I am not complaining about the complexity of the fitness or scoring function, I am complaining about trial and error approaches, when we have discovered a rocket for differentiation!

Re: Exploring Weight Agnostic Neural Networks

#18
post #12

How is it different than pruning a neural network? It seems you could train the weights of a state of the art NN, then quantizite it, then prune it. It will remove some weights of the NN, then all the remaining weights are set to the same value. Isn't training then pruning more efficient than using an architecture search algorithm ?

At the risk of broad oversimplification, pruning trains and then does an architecture search. This does an architecture search and then trains.

Re: Exploring Weight Agnostic Neural Networks

#19
post #6

Unpopular quote from my image and video processing professor - “The only problem with machine learning is that the machine does the learning and you don’t.” While I understand that is missing a lot of nuance, it has stuck with me over the past few years as I feel like I am missing out on the cool machine learning work going on out there. There is a ton of learning about calculus, probability, and statistics when doin…

I’m most excited about what is now being called scientific machine learning, ie machine learning models explicitly structured to learn interpretable models that can be used to understand some scientific domain better. For example, I’m starting to work on using graph RNNs to study dynamical behavior of reinforcement learning agents and how it might give us insights into psychiatric disorders.

Re: Exploring Weight Agnostic Neural Networks

#20
post #6

Unpopular quote from my image and video processing professor - “The only problem with machine learning is that the machine does the learning and you don’t.” While I understand that is missing a lot of nuance, it has stuck with me over the past few years as I feel like I am missing out on the cool machine learning work going on out there. There is a ton of learning about calculus, probability, and statistics when doin…

I'd suggest you look at Probabilistic programming languages: https://en.m.wikipedia.org/wiki/Probabilistic_programming

As someone who like you find ML boring, PPL is much more fascinating, because it brings the programming back into AI. It's more like the logical evolution of logic based rules system, adding bayesian probabilities to it.

Post reply on HN