12. Optimizers, Learning Rates & Callbacks with Fruit Classification/2. Types Optimizers and Adaptive Learning Rate Methods.srt

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OK so let's start of Chapter 11 point sorry twelve point one by looking at the types of optimizers we

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have available in Karris and look at some adaptive learning methods.

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So let's dive in.

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So optimizes what exactly optimizes.

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Now you may have remembered in a neural net explanation optimizes with the algorithm we use to minimize

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our loss.

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And some examples of this which I should be familiar to you know would be really in the sense stochastic

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really innocent and many batched.

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So Cara's actually comes with a lot more itemizes than those we have the standard stochastic Grilli

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and dissent armis Prop 8 a grad in adulthood.

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Adam Adam Max and Adam

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so in a quick aside about snow constant rates are generally bad especially if you start off too big.

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So I imagine after 50 long epochs ebox when we're thinking we're close to Convergence but then the problem

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is I will integrate basically bounces around and loss and our sorry our training center at Teslas So

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basically stop increasing.

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That's a bad situation.

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When you're training so you always want to use a learning rate that's small as small as possible without

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being too small because it's too small or small of learning.

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It would just simply take forever to train.

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So there's so many choices.

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What's the difference.

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The main difference in these algorithms is how they manipulate learning rates to allow faster convergence

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and better validation accuracy.

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Some require like a gradient descent setting off some manual parameters or even adjusting or learning

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which you will come to shortly and then some of them use a stick approach to provide adaptive learning

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rates which are quite cool.

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We'll actually see some of the comparisons shortly.

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So let's talk a bit about stochastic really and descent and the parameters Karris allows us to control.

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So by default cursor uses a constantly integrates in SAGD itemizes at stochastic really and descent

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and however we can set these parameters off momentum to key and also turn off or on something called

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noster of momentum.

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So let's talk about a bit about momentum.

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Momentum is a technique that accelerates SAGD by pushing degree and steps along the relevant direction

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but reducing the jump in oscillations away from relevant directions.

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So basically it basically encourages O'Grady and descent to head into the direction that is basically

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reducing loss.

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So it doesn't actually go away from that spot.

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And big jumps at least to kids is something that the kids are able great every batch of it not Iput

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Depok.

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So be careful how you set about size.

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By the way.

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This is it only at a time but size becomes relevant in training.

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A good rule of thumb though is for setting the Dekhi is equal to leaning read divided by a number of

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ebox.

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OK.

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So that's how we choose the key value noster off basically is a guy who actually developed a method

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that solves the problem of oscillating around r.m.r not us losing oscillating around on minima basically

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means getting rid of too big for us to actually converge at a minimum point.

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And this happens when a minute momentum is high and unable to slow down.

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So this makes a big jump then a small correction and after that the gradient is calculated.

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That's not Esther of weeks.

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So all of those encourage you to use Nassor of being if you actually want to get fast to.

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So this is a good illustration here of Nestor off woman to illustrate it.

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It was taken from this source it seems to try one stone for its course.

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So basically this is actually all the other algorithms combined here.

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And basically it shows you how women actually looks as well.

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So take a look.

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It's actually quite interesting.

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This is SDD Witt moment with sort of enabled by the way so you can see it's taking a while to get here.

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But it will eventually get here although the others have gotten their way quickly.

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I actually was wrong in one thing.

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I just remember them taking it on my second screen.

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Actually no momentum actually had noster of enabled here.

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SDD was just plain vanilla yesterday.

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So I can see all of these advanced optimizers got there eventually except for yesterday which took forever.

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So let's talk a bit about more of those other algorithms here.

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Some of these here.

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Let's start talking about the ones that are available in Paris.

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So we just saw we set up parameters to control that getting Richard you and living Richard ules are

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basically either.

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How are we leading rates adapt over to treating process based be it based on number of e-books have

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been completed or other parameters.

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OK.

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That's why it's adaptive learning repentance and each book differently.

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So let's talk quickly about that.

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This performs large of the more sparse parameters and smaller of the ads for less pass parameters.

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Is this actually about English.

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It is the Tuss it is us well-suited for spazzed do how ever will because the learning rate is always

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decreasing monotonically after many books learning slows down to a crawl.

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So it adults actually solves this monotonically decreasing gradient basically an integral and occurs

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in allograft armis proper is actually similar to integrate it adults.

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Sorry couldn't find much information to explain this but just remember these are similar probably discovered

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and have similar discovered separately but have similar methods of action an atom which is not really

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item its name but item it's similar to either Delta but still has momentum for learning rates for each

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parameter.

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Each of the parameters separately.

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I'll correct these little mistakes here and there before this should be decided to you guys.

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So what does a good learning read look like.

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So this is Holan a loss graph here.

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Epoxied This is how it would look if we had a very high rate a large rate.

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Basically we would never find a convergence zone because we'd be bouncing around everywhere and a lot

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of problem just get worse over time.

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A little learning it will eventually get there however it'll take a while.

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Highly integrated will eventually get here too.

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But this could actually could be interchangeable but basically it will get here to good living rates

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have nice gradual smooth and decreasing steps and basically converge at lower points over time.

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And finally if you go to Icarus you slash optimizes it brings up a list of all optimizes and actually

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how to use decode here and how to what settings that are available to optimize this so you can see as

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she does here basically we have some of these parameters here.

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Noster of decie I mentioned to you before.

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Armis prop all of these are available here and some explanations on what they do what to what you can

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tweak is all available on Kerrison site.

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So take a look.

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Just so you know in best practice I find Adam to be one of the best optimizers.

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I don't even actually have to go for or from these default values.

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I actually just put it to be slightly smaller.

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But all these values are usually fine also what's quite good to use as well is SAGD with a very low

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living rate.

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You can set the momentum and key according to your parameters.

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I mentioned before and always used sort of as true.