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Stanford A.I. Courses

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Re: Stanford A.I. Courses

#51

Are there project-based tutorial that talks more about neural net architecture, hyperparameters selection and debugging? Something that walks through getting poor results and make explicit the reasoning for tweaking? When I try to use transformers or any AI thing on a toy problem I come up with, it never works. Even Fizz-Buzz which I thought was easy doesn't work (because division or modulo is apparently hard to repr…

Yes. I created a course which uses implementing Stable Diffusion from scratch as the project, and goes through lots of architecture choices, hyperparam selection, and debugging. (But note that this isn't something that's fast or easy to learn - it'll take around a month full-time intensive study.) https://course.fast.ai/Lessons/part2.html

Re: Stanford A.I. Courses

#52
post #12

Looking for guidance here. There are a lot of courses out there on AI from esteemed institutions at that. What do people recommend as a curriculum for someone with a formal univ education in CS albeit from a while ago and who has programmed extensively though not in Python. The goal at the end is to have a deep understanding of the LLM space and its adjacencies.

Although I myself am not related to the industry or academia pertaining to AI, I have heard many people speak highly of the zero to hero course by Andrej Karpathy: https://youtube.com/playlist?list=PLAqhIrjkxbuWI23v9cThsA9Gv... I myself loved it and learned a lot, but YMMV

That course is fantastic. Just don't be afraid to pause and rewatch. It took me a long time to get through the first three videos.

Re: Stanford A.I. Courses

#53

Are there project-based tutorial that talks more about neural net architecture, hyperparameters selection and debugging? Something that walks through getting poor results and make explicit the reasoning for tweaking? When I try to use transformers or any AI thing on a toy problem I come up with, it never works. Even Fizz-Buzz which I thought was easy doesn't work (because division or modulo is apparently hard to repr…

There's no great answer to this question. It is a bunch of tricks. Fundamentally: If you're saying FizzBuzz doesn't work, presumably you mean that encoding the n directly doesn't work. Neither does encoding n from 0 to 1 or between -1 and 1 (and don't forget: obviously don't use relu with -1 to 1). It doesn't. Neural networks can do a LOT of things, but they cannot deal with numbers. And they certainly cannot deal wi…

> This may be catastrophically wrong. I only have a master's in machine learning (a European master's degree, meaning I've written several theses on it (didn't pass first time, had to work full time to be able to study), and I was writing captcha crackers using ConvNets in 2002. But I've never been able to convince anyone to hire me to do anything machine learning related.

Oh wow, those are great credentials. I'm surprised that you haven't run across a position yet. Maybe it is a matter of your location? It seems like a lot of these jobs want onsite workers, which can be a real problem.

TBH, I get the feeling that a lot of us without such credentials are in a similar position right now. Slowly trying to work our way towards what seems to be a big new green field, but having a really unclear path to getting there...

Re: Stanford A.I. Courses

#54
post #36

Earlier quoted context omitted.

I took a deep learning course in late 2019, during which we implemented transformers as described in Attention is All You Need and fine-tuned GPT-2. The output was amusing, but useless, but I still remember the basic principles. Now, a few years later, transformers are the tech, and GPT-2's successors are the most hyped technologies of the century so far. All of which is to say that I wouldn't assume that coursework…

I mean if someone likes the subject, then they should invent a project that forces them to build something or write something up. Otherwise its easy to "fake" learning by doing the motions on a bunch of tutorials and quizzes.

It really depends how good the course is, with well-designed problem sets/project prompts you can't really fake learning (assuming you actually complete them). Is it going to be totally exhaustive of everything you may need to know in practice? Obviously not, but no single project will be either, especially not for such a broad field as machine learning.

Independent projects can definitely be a great way to learn, and yes many courses are shitty. But it is also very possible to take a good course and walk away with new knowledge you didn't even realize you needed. Some of my favorite projects actually started with an idea from a course, and then I learned even more in order to further expand on it. Synergy between project-driven and course-driven education can be a powerful iterative process.

Re: Stanford A.I. Courses

#55

Why is Convex Optimization (EE364a) not included? https://stanford.edu/class/ee364a/ https://www.youtube.com/playlist?list=PL3940DD956CDF0622 It's one of the best courses to take if you want to obtain some fundamental understanding of the mathematical concepts behind AI. Yes there's much more to it than NNs/transformers/'Attention is all you need' paper/whatever else is trendy right now. No, don't expect to do import…

I hate academic trend following as much as anyone, but is it really true people are not employable in this space if they don't understand mathematical foundations? Sure, they're not getting a job at DeepMind, but it feels like there are many successful ML grifters these days too. Maybe I'm just on Twitter too much.

Re: Stanford A.I. Courses

#56
post #14

I think the way courses are taught can give you some needed grounding, like you should always take a good linear regression class. But I think that is as far as it gets you, a theoretical base. Honestly the issue is that most ML programs are taught as being some kind of additive skill set: the more courses you take the better or selection of the right kind of courses gets you some where. In reality: 1. most real worl…

> like you should always take a good linear regression class.

Any recommendations for a _good_ linear regression class / course?

Re: Stanford A.I. Courses

#57
post #26

Care to explain cross entropy simply? That’s where I paused currently

Shooting from the hip:

entropy of a single signal, say a sequence of letters, "ababababab" is the scaled "average" surprise per letter. So if they are uniformly distributed, each letter is equally likely/unlikely to come next in the sequence, where if instead one letter only 1/1000th of the time (aaa....aaa...aa..a.z.aaaa), then when the rare beast shows up, it is a big surprise, so the total amount of surprise available in the sequence is high.

That's entropy.

The same thing would be true for a sequence of numbers.

But what if there is some relationship? if aaabaa occurs frequently with 111211, if you line up the sequences by timestamp?

In this simple case, if you know the letters and you can spot the relationship, then there is zero surprise in the number sequence. The cross entropy "letters plus numbers" has the same entropy as "letters" or "numbers" in isolation.

And as you move away from the 1:1 correspondence, you'll see the cross entropy increase until it reaches its max at "entropy(letters) + entropy(numbers)" -- no information shared between the two systems.

To bring it home, I think of cross entropy as the amount of information shared between two signals.

Others might think of it slightly differently.

Re: Stanford A.I. Courses

#58

Earlier quoted context omitted.

> The goal at the end is to have a deep understanding of the LLM space and its adjacency. This is kinda a hard thing to quantify. How are we defining deep? Like you want to understand how they work? The Karpathy videos are good for that. But I wouldn't call this "deep". If you want to get down into the weeds and into the mud, you need a hell of a lot more than 13hrs of education. You're also going to have a hard time…

Thanks for the helpful advice. What would you recommend to someone who is interested in learning about diffusion models? I have a CS degree but I have 0 knowledge about AI. Things like Stable Diffusion have blown my mind and I’m really interested in learning about this field. Lots of courses out there but I lack the expertise to discern which one is good.

Yeah no problem, this is even closer to my area of focus! What do you know about physics and thermodynamics?

I'd say a good intro for low background is from Tomczak[0]. He has a book, but the blog posts are nearly identical. He did a post doc with Max Welling (someone you should learn about if you want to get deep, like I was suggesting before). So I'd switch things up slightly. I'd go Intro -> Autoregressive -> Flow -> VAE -> Hierarchical VAE -> Energy Based Models -> Diffusion. It is worth learning about GANs btw, but this progression should be natural and build up.

Continuing from there, you're going to want to learn about things Langevin Dynamics, Score Matching, and so on. Start with Yang Song's blogs[1]. Your goal should be to understand this paper[2]. Once you get there, you should be able to understand the famous DDPM paper[3]. But why we went through Tomczak wasn't just to get a good understanding of diffusion at a deeper level, but because you need these tools to understand Stable Diffusion which really is just Latent Diffusion[4]. This should connect back with Tomczak's 2 Improving VAE papers and you should also be able to understand NVAE.

This is probably the quickest way to get you to a good understanding but if you want to dig deeper, which I highly encourage (because there are major issues that people aren't discussing) then you'll need more time. But you'll probably have to tools to do so if you go through this route. Other people I suggest looking into: Diederik Kingma, Ruiqi Gao, Stefano Ermon, Jonathan Ho, Ricky T. Q. Chen, and Arash Vahdat.

[0] https://jmtomczak.github.io/

[1] https://yang-song.net/

[2] Deep Unsupervised Learning using Nonequilibrium Thermodynamics https://arxiv.org/abs/1503.03585

[3] https://arxiv.org/abs/2006.11239

[4] High-Resolution Image Synthesis with Latent Diffusion Models https://arxiv.org/abs/2112.10752

Re: Stanford A.I. Courses

#60
post #14

I think the way courses are taught can give you some needed grounding, like you should always take a good linear regression class. But I think that is as far as it gets you, a theoretical base. Honestly the issue is that most ML programs are taught as being some kind of additive skill set: the more courses you take the better or selection of the right kind of courses gets you some where. In reality: 1. most real worl…

> like you should always take a good linear regression class. Any recommendations for a _good_ linear regression class / course?

https://www.coursera.org/learn/linear-regression-model

https://www.coursera.org/specializations/machine-learning-in...

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