We come back. 
Discrete Optimization, Mail Bag Week 3. 
I'm very happy to, have you back here. 
you may wonder why I am invisible, 
actually I'm not invisible. 
I'm in a conference in the Yellow 
Mountain in China. 
But you see, I can't keep thinking about 
Cousera. 
And that's why we really wanted to send 
you this mail bag. 
Okay? 
Stay tuned. 
You won't see me, but I'm there. 
So, first things first, key announcement 
please take the mid-course survey. 
We are the middle you know, just in the 
middle of the class. 
We want you to give as much feedback as 
you can. 
You are the active students, see if you 
are listening to me right now. 
And we want to hear from you to make the 
next part of the classes move as 
possible. 
I'm going to update you, with the number 
of statistic, the number of active 
students now is around 9000. 
You know, some decrease compared to last 
week, nothing that we didn't expect this 
is the hard part of the class right now. 
some more statistic about the videos and, 
and, the various mail bags that I've been 
seeing. 
For instance, 2,000 views of the second 
mail bag last week, about 13,000 views of 
the introductory video. 
Thinks you know, people are looking at 
this. 
this is the number of students active in 
assignment this is decreasing, obviously. 
you can see that we had another decrease 
from [UNKNOWN] another decrease for TSP, 
this is absolutely what we anticipated. 
These are the toughest assignment of the 
class. 
these are the number of submission 
graded, they are also decreasing with the 
number of students obviously. 
This is the slide which is actually 
pretty interesting, this is the number of 
submission per active students, and what 
you can see that, the students who are 
active are very active. 
Okay, so what the, what the graph is 
showing that they are more active. 
Obviously this is an average so, they may 
stay as active as, as before but the 
average is increasing. 
This is what we want to see, this is very 
reassuring. 
This is the slides that we like the most. 
what you see over there is about 13,000 
assignments all graph colored, this is 
terrific guys. 
this means that there are a lot of 
students in this class who are really 
dedicated and are trying to get through 
this material and these assignments which 
are really difficult. 
As we told you, graph coloring is a 
nightmare, as you have experienced. 
so keep going you know, keep progressing, 
we want more numbers for the TSPs. 
this is also an interesting slide in a 
sense, so what you see on x-axis are the 
number of points awarded so far. 
And on the y-axis is basically the total 
number of students which ever will be 
awarded to these points. 
And so, what you can see is that they are 
about 1000 students that are above 
threshold as far as, as the assignments 
are concerned at graphical coloring. 
So, the vertical lines you see there, are 
basically the great, you should have, the 
number of points that you should have for 
having a passing grade in the class. 
And so, you are seeing that it has been 
sharply decreasing for graph coloring, 
and once again no big surprise because 
this is what we expected. 
But we are above the thousand mark for 
graph coloring and they, this is exactly 
where we want to be. 
And so, what we need to do is to lift 
this blue curve, so that it stays above 
10,000 well, above 1000 for everyone of 
the other assignments. 
This is really the goal of this class. 
The dream that we have we'd like to give 
out a 1,000 certificates. 
And obviously the problem that we have is 
we can't lower our standards, we don't 
want to lower the standards we want to 
make this class you know, as, as hard as 
a senior undergraduate or a beginning 
graduate class. 
In a, you know, very high standards of 
you know, university and, and therefore 
we don't want to lower these standards. 
But we do everything we can to help you 
succeed and meet these goals. 
And so, in a sense you know, for doing 
this, we're going to do two things. 
So, the first thing we're going to do is 
that we will be adjusting the stereo 
slightly, which will allow more time for 
the TSP. 
Let you guys breathe a little bit, get 
this TSP you know, up to above the 1000 
mark. 
And also, if you are successful in these 
assignments, go to the website and give 
tips to other people, you can. 
So, we encourage collaboration 
obviously,we encourage people talk about 
their solution,the final problem should 
be your own. 
But you can discuss solutions with other 
people, you can give tips to other 
people, you can guide them towards good 
solution. 
So, this is one of the things we had in 
the, in the University version of this, 
of this class. 
So, people, we had this session where 
people could, you know, tell other people 
what they were doing. 
It's very good to actually share your 
experience. 
You don't have to give all the tricks, 
but you can say, oh, I tried this and 
this worked very well for me. 
so, this is the new schedule, so we are 
pushing TSP a little bit back you know, 
pushing every one of the future 
assignment by one week. 
Obviously, this is a you know, eight week 
schedule so, [INAUDIBLE] one final week 
for tuning everything. 
So, we are basically adding this week and 
we want to add it at this point. 
Because this is the point where we 
believe it makes the most sense. 
People can breathe a little bit more, 
they can focus on TSP. 
Get above this 1000 mark and then we 
gotta get close to the dream that we have 
of putting all these students through 
the, through the entire class and getting 
their certificates. 
once again, you know, I want people to 
collaborate, we want a lot of people 
interacting on the forum. 
What you see there, you know, some great 
threats where you know, people are 
talking about the implementation of graph 
coloring. 
People talking about the implementation 
of TSP and [UNKNOWN] on TSPs and things 
like that. 
Check those things. 
There is a lot of information of the on 
the, on the forum and please you know, 
you can volunteer that kind of 
information and tell people the kind of 
things that you have been doing. 
So, these three threads, look at them, 
they are interesting. 
They give you a lot of feedback, they 
also speed up your work tremendously. 
Okay, so what's next? 
Continue enjoying traveling salesman 
problem. 
It's tog also it's time also to start 
looking at the LP and the MIP lectures 
such that you will get on top of those 
before you do the warehouse location 
assignment. 
And you know, have fun, I think this is 
this is going really well. 
I think we have a lot of dedicated 
students we want to bring you know, these 
1000 students above that mark that's the 
goal that we have. 
Okay guys, have fun you know, keep going 
we are very happy.