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Google Vizier: A Service for Black-Box Optimization

ai.google

41–50 of 86 posts

Re: Google Vizier: A Service for Black-Box Optimization

#41

Only up to 64 variables? Why such small problems? And why are their results are averaged across all of the different test functions? I'd like to see the performance difference between Rosenbrock and Rastrigin, thank you very much. And they have a weird fixation on stopping rules, when in general your stopping rule is how many evaluations you can afford. Was this written by interns? There's no discussion of the retrog…

To expand on ScoutOrgo,

>Only up to 64 variables? Why such small problems?

This is a tool tuned for optimizing the hyperparameters of machine learning models. In practice, most models have, maybe, 10 hyperparameters in the normal sense (learning rate, nonlinearity, etc.). If you start talking about model structure as a hyperparameter, you can get vastly more than 64, but then these techniques aren't great anyway.

So why such small problems? Because the blackbox function you're optimizing takes hours to run. So as another user mentions, if it takes you 700 function evaluations, you're gonna be running for the better part of a year.

So the domain over which vizier works is one where you probably are never really using more than ~100 evaluations and often even then you would prefer to stop early if you meet certain conditions (because wasting significant compute doing unnecessary optimization is costly).

As a concrete example, a single iteration of a relatively small and non-SOTA algorithm takes 20 minutes and $40 to run. [0]

So stopping a day early saves you a day and $3000. Now scale that up 5 or 10x for larger models. (another way of putting this is that a day and $10K might be worth a .5% increase in accuracy, but isn't worth a .05% increase in accuracy. Stopping rules can encode that).

[0]: http://www.fast.ai/2018/08/10/fastai-diu-imagenet/

Re: Google Vizier: A Service for Black-Box Optimization

#42

Okay, this is awesome (and easy to miss with a just a cursory skim): "5.3 Delicious Chocolate Chip Cookies Vizier is also used to solve complex black–box optimization problems arising from physical design or logistical problems. Here we present an example that highlights some additional capabilities of the system: finding the most delicious chocolate chip cookie recipe from a parameterized space of recipes... We prov…

I worked for Google at the time they went through the cookie iterations in the cafes. Personally I disliked all the cookies that ever came out of this project, mainly because they contained spices, I heard the same thing from many others. After you got handed a cookie you were asked to fill out a feedback form on a tablet, which almost always is annoying. But more importantly, the process of optimizing the ingredient…

Sounds like you got the less tasty side of the explore/exploit tradeoff.

Re: Google Vizier: A Service for Black-Box Optimization

#43

Only up to 64 variables? Why such small problems? And why are their results are averaged across all of the different test functions? I'd like to see the performance difference between Rosenbrock and Rastrigin, thank you very much. And they have a weird fixation on stopping rules, when in general your stopping rule is how many evaluations you can afford. Was this written by interns? There's no discussion of the retrog…

It is 64 hyper-parameters, not variables, which is a huge amount. Stopping rules are also a requirement of tuning. Can't just have a while True:. If an objective function doesn't improve after 100 (or any #), there needs to be logic to stop the trials since this system is apparently serving all of Alphabet.

Surely that reinforces my point? That what matters isn't the stopping rule but your evaluation budget? If you can afford 100 evaluations, do 100 evaluations. Pick any stopping rule based on the objective function and I can construct you a scenario that either has you spending a long time on the wrong side of it, or stopping prematurely. Might as well have predictable behavior.

Re: Google Vizier: A Service for Black-Box Optimization

#44
post #39
post #16

Earlier quoted context omitted.

It's great that they published this - I wasn't sure if I could share this externally. I see they left the ingredient that really improved the scores unexpectedly out, presumbly for proprietary reasons.

You're not thinking of these gluten-free cardamom cookies? https://www.blog.google/technology/research/makings-smart-co...

That ingredient list is missing the "secret ingredient" that your parent post is talking about, so nah.

Re: Google Vizier: A Service for Black-Box Optimization

#45
post #7
post #4

Earlier quoted context omitted.

I noted this section when I read the paper as well... This is cute, but "in the authors' opinions, delicious" does not contribute anything to scientific research. Yes, you can use black-box optimization for cookie recipes. No, you should not make any sort of performance claims nor talk about "significant" improvement unless you back it up.

Their back up: later rounds were extremely well-rated

How about "My brand new image recognition architecture performs extremely well on benchmarks"

But it's worse than the last 100 SOTA models...

Re: Google Vizier: A Service for Black-Box Optimization

#46
post #8
post #4

Earlier quoted context omitted.

I noted this section when I read the paper as well... This is cute, but "in the authors' opinions, delicious" does not contribute anything to scientific research. Yes, you can use black-box optimization for cookie recipes. No, you should not make any sort of performance claims nor talk about "significant" improvement unless you back it up.

> in the authors' opinions, delicious Can there be/Is there an objective way to measure deliciousness? If not what can they really say?

> Cafe goers tasted the cookies and provided feedback via a survey. Survey results were aggregated and the results were sent back to Vizier.

This, from the paper, is a great start on measuring deliciousness. But if you go to that effort, why not provide a benchmark? Such as the existing chocolate chip cookie recipe or the average scores from 10 random chocolate chip cookie recipes?

As a reader, I might suspect that performance was not that great compared to baselines but that the authors were able to mask it by making this qualitative claim ("the cookies were delicious") -- which I'm sure was still true!

Re: Google Vizier: A Service for Black-Box Optimization

#47

Very related open source project from the RISE Lab at UC Berkeley: http://ray.readthedocs.io/en/latest/tune.html

Very cool project! Glad to see support for PBT and HyperBand. Also related to https://www.microsoft.com/en-us/research/publication/hyperdr...

Re: Google Vizier: A Service for Black-Box Optimization

#48

This product is publicly available as a part of the hyperparameter turning in Cloud ML Engine (although I haven't played with it): https://cloud.google.com/ml-engine/docs/tensorflow/hyperpara...

Why do you think it is vizier, and not something developed specifically for clous?..

Re: Google Vizier: A Service for Black-Box Optimization

#49

This product is publicly available as a part of the hyperparameter turning in Cloud ML Engine (although I haven't played with it): https://cloud.google.com/ml-engine/docs/tensorflow/hyperpara...

Why do you think it is vizier, and not something developed specifically for clous?..

If you click through the explanation in the documentation:

> Cloud Machine Learning Engine is a managed service that enables you to easily build machine learning models that work on any type of data, of any size. And one of its most powerful capabilities is HyperTune, which is hyperparameter tuning as a service using Google Vizier.

https://cloud.google.com/blog/products/gcp/hyperparameter-tu...

Re: Google Vizier: A Service for Black-Box Optimization

#50
post #8
post #4

Earlier quoted context omitted.

I noted this section when I read the paper as well... This is cute, but "in the authors' opinions, delicious" does not contribute anything to scientific research. Yes, you can use black-box optimization for cookie recipes. No, you should not make any sort of performance claims nor talk about "significant" improvement unless you back it up.

> in the authors' opinions, delicious Can there be/Is there an objective way to measure deliciousness? If not what can they really say?

This really assumes that there is one-true-deliciousness factor, which is patently false if the spaghetti sauce optimization exists. (in which the previously unknown chunky sauce actually was discovered to be a non-trivial market segment)

This seems more like a spanning/optimization problem (how to cover the majority of preferences while not needing too many varieties) than an actual optimization problem, but then again it's just a sample use case to use to sell their API, so they probably didn't think too hard about it.

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