-: Hello, and welcome to the final level
of the self-driving car challenge.
So this time my goal will be to beat the self-driving car
not the level four, because I want to challenge you
into improving the code, improving the AI
or maybe improving the strategy
so that you can beat this challenge yourself.
So I'm going to make a highly complex road
that will still go from the airport to the downtown
but maybe too complicated for the car to find its way.
So that will be my challenge, so
that I hope you can have fun with a challenging homework.
So let's do this.
Let's approach this level four.
So let's select everything, then let's load the brain.
And there we go.
Now it's doing the round trips
between the airport and the downtown.
So it's gonna take some time.
So I'm just gonna put
on some music and here we go with the road.
(gentle music)
And there we go.
Here is the road.
And as you can see, the car seems to have a lot
of trouble so that's exactly what I wanted.
It's, you know, doing this little round trips
in the same part of the road.
So that's a problem.
It doesn't find its way right now to the downtown.
So how can we fix this?
Can we, do we need to change the strategy?
Do we need to change the parameters
of the neural networks that has changed the synapses
in the brain of the car?
Do we need to do something with the rewards?
You know, maybe get a worse reward
when it's not finding the goal as it is the case right now?
So so I don't know.
That's for you to find out.
As you can see, the rewards is not very severe
when it's not finding the goal, you know
and it's not getting closer to the goal.
The reward is just minus oh 0.2.
So that's not a severe bad reward.
You could try to decrease the reward even more
like setting a reward equals
to minus oh 0.5, maybe that will work.
I'm just throwing some suggestions to help you.
So that's a change you can make with the reward strategy.
And then of course
you can make some other changes with your neural network.
So you know, in this section we create the architecture
of the neural network,
we choose to have 30 hidden neurons in one hidden layer.
Maybe you can try to change the architecture
by trying some more layers or some more hidden neurons,
I don't know.
So that's another suggestion for improvement.
And then you can also try to change something
in a deep key learning algorithm, or simply you can move
on to the course and find out about the other algorithms.
Maybe there is another one
that will manage to handle this situation.
So good luck.
I look forward to seeing your solutions.
Try to draw that same road, that's perfect,
that's really pretty exciting enigma.
And if you want me to give you a hint, or
if you want me to explain quickly what the problem is,
well you can see that right here.
When it reaches that point, it's going back.
And that's because when it's reaching
that point it's getting too far away
from the goal which right now is the downtown.
You know, when it's reaching that point, if it goes further,
well it will go further away from the goal.
So that's why it's going back here.
And so you have to change something in a code,
something in a strategy to maybe punish it less
when it's getting further away from the goal.
Maybe that's a solution.
I'm just throwing some suggestions.
I don't want to give you the solution too fast
but that would be a really good exercise.
And that's typically a problem that can be encountered
by the engineers when they're making a self-driving car.
But anyway, I think that's a pretty cool enigma.
So I hope you will have fun.
And before solving this homework
maybe you can do another very efficient homework
which would be simply to try to implement all this AI again
you know, just implement the exact same one.
That will be excellent practice
because so far you've just listened to my explanations
but there is a huge difference between listening
to something and try to do the thing ourself.
Oh, oh, did you see what happened?
It just found its way.
That's amazing.
It's funny how it's got out of it
but I'm sure there is a better strategy
to get out of it more efficiently.
And now it seems to be pretty good.
Maybe I'm speaking too fast.
Maybe it's going to solve this.
No, here we go.
It's getting stuck here again.
That's pretty challenging for the car, right?
But I'm sure this can be solved.
That's your goal, so good luck,
and please let me know about your solutions.
Until then, enjoy AI.
(gentle music)