1 00:00:00,810 --> 00:00:03,490 We come back. Discrete Optimization, Mail Bag Week 3. 2 00:00:03,490 --> 00:00:10,299 I'm very happy to, have you back here. you may wonder why I am invisible, 3 00:00:10,299 --> 00:00:15,426 actually I'm not invisible. I'm in a conference in the Yellow 4 00:00:15,426 --> 00:00:19,428 Mountain in China. But you see, I can't keep thinking about 5 00:00:19,428 --> 00:00:22,150 Cousera. And that's why we really wanted to send 6 00:00:22,150 --> 00:00:24,050 you this mail bag. Okay? 7 00:00:24,050 --> 00:00:26,890 Stay tuned. You won't see me, but I'm there. 8 00:00:26,890 --> 00:00:30,360 So, first things first, key announcement please take the mid-course survey. 9 00:00:30,360 --> 00:00:33,250 We are the middle you know, just in the middle of the class. 10 00:00:33,250 --> 00:00:35,450 We want you to give as much feedback as you can. 11 00:00:35,450 --> 00:00:38,200 You are the active students, see if you are listening to me right now. 12 00:00:38,200 --> 00:00:42,247 And we want to hear from you to make the next part of the classes move as 13 00:00:42,247 --> 00:00:45,768 possible. I'm going to update you, with the number 14 00:00:45,768 --> 00:00:49,050 of statistic, the number of active students now is around 9000. 15 00:00:49,050 --> 00:00:52,884 You know, some decrease compared to last week, nothing that we didn't expect this 16 00:00:52,884 --> 00:00:58,486 is the hard part of the class right now. some more statistic about the videos and, 17 00:00:58,486 --> 00:01:02,708 and, the various mail bags that I've been seeing. 18 00:01:02,708 --> 00:01:07,197 For instance, 2,000 views of the second mail bag last week, about 13,000 views of 19 00:01:07,197 --> 00:01:12,045 the introductory video. Thinks you know, people are looking at 20 00:01:12,045 --> 00:01:14,484 this. this is the number of students active in 21 00:01:14,484 --> 00:01:19,514 assignment this is decreasing, obviously. you can see that we had another decrease 22 00:01:19,514 --> 00:01:25,540 from [UNKNOWN] another decrease for TSP, this is absolutely what we anticipated. 23 00:01:25,540 --> 00:01:28,940 These are the toughest assignment of the class. 24 00:01:28,940 --> 00:01:32,357 these are the number of submission graded, they are also decreasing with the 25 00:01:32,357 --> 00:01:36,407 number of students obviously. This is the slide which is actually 26 00:01:36,407 --> 00:01:40,117 pretty interesting, this is the number of submission per active students, and what 27 00:01:40,117 --> 00:01:44,570 you can see that, the students who are active are very active. 28 00:01:44,570 --> 00:01:47,960 Okay, so what the, what the graph is showing that they are more active. 29 00:01:47,960 --> 00:01:51,425 Obviously this is an average so, they may stay as active as, as before but the 30 00:01:51,425 --> 00:01:55,312 average is increasing. This is what we want to see, this is very 31 00:01:55,312 --> 00:01:59,230 reassuring. This is the slides that we like the most. 32 00:01:59,230 --> 00:02:03,242 what you see over there is about 13,000 assignments all graph colored, this is 33 00:02:03,242 --> 00:02:06,570 terrific guys. this means that there are a lot of 34 00:02:06,570 --> 00:02:09,834 students in this class who are really dedicated and are trying to get through 35 00:02:09,834 --> 00:02:14,521 this material and these assignments which are really difficult. 36 00:02:14,521 --> 00:02:18,390 As we told you, graph coloring is a nightmare, as you have experienced. 37 00:02:18,390 --> 00:02:23,480 so keep going you know, keep progressing, we want more numbers for the TSPs. 38 00:02:23,480 --> 00:02:27,110 this is also an interesting slide in a sense, so what you see on x-axis are the 39 00:02:27,110 --> 00:02:32,916 number of points awarded so far. And on the y-axis is basically the total 40 00:02:32,916 --> 00:02:38,016 number of students which ever will be awarded to these points. 41 00:02:38,016 --> 00:02:42,916 And so, what you can see is that they are about 1000 students that are above 42 00:02:42,916 --> 00:02:49,665 threshold as far as, as the assignments are concerned at graphical coloring. 43 00:02:49,665 --> 00:02:54,357 So, the vertical lines you see there, are basically the great, you should have, the 44 00:02:54,357 --> 00:03:00,750 number of points that you should have for having a passing grade in the class. 45 00:03:00,750 --> 00:03:04,325 And so, you are seeing that it has been sharply decreasing for graph coloring, 46 00:03:04,325 --> 00:03:08,640 and once again no big surprise because this is what we expected. 47 00:03:08,640 --> 00:03:12,215 But we are above the thousand mark for graph coloring and they, this is exactly 48 00:03:12,215 --> 00:03:15,706 where we want to be. And so, what we need to do is to lift 49 00:03:15,706 --> 00:03:19,411 this blue curve, so that it stays above 10,000 well, above 1000 for everyone of 50 00:03:19,411 --> 00:03:23,760 the other assignments. This is really the goal of this class. 51 00:03:23,760 --> 00:03:28,250 The dream that we have we'd like to give out a 1,000 certificates. 52 00:03:28,250 --> 00:03:31,682 And obviously the problem that we have is we can't lower our standards, we don't 53 00:03:31,682 --> 00:03:34,958 want to lower the standards we want to make this class you know, as, as hard as 54 00:03:34,958 --> 00:03:39,387 a senior undergraduate or a beginning graduate class. 55 00:03:39,387 --> 00:03:42,767 In a, you know, very high standards of you know, university and, and therefore 56 00:03:42,767 --> 00:03:47,285 we don't want to lower these standards. But we do everything we can to help you 57 00:03:47,285 --> 00:03:50,660 succeed and meet these goals. And so, in a sense you know, for doing 58 00:03:50,660 --> 00:03:53,760 this, we're going to do two things. So, the first thing we're going to do is 59 00:03:53,760 --> 00:03:56,576 that we will be adjusting the stereo slightly, which will allow more time for 60 00:03:56,576 --> 00:04:00,265 the TSP. Let you guys breathe a little bit, get 61 00:04:00,265 --> 00:04:04,260 this TSP you know, up to above the 1000 mark. 62 00:04:04,260 --> 00:04:07,626 And also, if you are successful in these assignments, go to the website and give 63 00:04:07,626 --> 00:04:11,359 tips to other people, you can. So, we encourage collaboration 64 00:04:11,359 --> 00:04:14,980 obviously,we encourage people talk about their solution,the final problem should 65 00:04:14,980 --> 00:04:17,954 be your own. But you can discuss solutions with other 66 00:04:17,954 --> 00:04:20,821 people, you can give tips to other people, you can guide them towards good 67 00:04:20,821 --> 00:04:23,798 solution. So, this is one of the things we had in 68 00:04:23,798 --> 00:04:27,080 the, in the University version of this, of this class. 69 00:04:27,080 --> 00:04:30,380 So, people, we had this session where people could, you know, tell other people 70 00:04:30,380 --> 00:04:33,967 what they were doing. It's very good to actually share your 71 00:04:33,967 --> 00:04:36,311 experience. You don't have to give all the tricks, 72 00:04:36,311 --> 00:04:40,140 but you can say, oh, I tried this and this worked very well for me. 73 00:04:40,140 --> 00:04:45,098 so, this is the new schedule, so we are pushing TSP a little bit back you know, 74 00:04:45,098 --> 00:04:50,200 pushing every one of the future assignment by one week. 75 00:04:50,200 --> 00:04:53,804 Obviously, this is a you know, eight week schedule so, [INAUDIBLE] one final week 76 00:04:53,804 --> 00:04:57,854 for tuning everything. So, we are basically adding this week and 77 00:04:57,854 --> 00:05:01,370 we want to add it at this point. Because this is the point where we 78 00:05:01,370 --> 00:05:04,844 believe it makes the most sense. People can breathe a little bit more, 79 00:05:04,844 --> 00:05:08,045 they can focus on TSP. Get above this 1000 mark and then we 80 00:05:08,045 --> 00:05:11,785 gotta get close to the dream that we have of putting all these students through 81 00:05:11,785 --> 00:05:16,660 the, through the entire class and getting their certificates. 82 00:05:16,660 --> 00:05:19,860 once again, you know, I want people to collaborate, we want a lot of people 83 00:05:19,860 --> 00:05:23,989 interacting on the forum. What you see there, you know, some great 84 00:05:23,989 --> 00:05:27,434 threats where you know, people are talking about the implementation of graph 85 00:05:27,434 --> 00:05:31,125 coloring. People talking about the implementation 86 00:05:31,125 --> 00:05:34,370 of TSP and [UNKNOWN] on TSPs and things like that. 87 00:05:34,370 --> 00:05:37,011 Check those things. There is a lot of information of the on 88 00:05:37,011 --> 00:05:40,173 the, on the forum and please you know, you can volunteer that kind of 89 00:05:40,173 --> 00:05:45,220 information and tell people the kind of things that you have been doing. 90 00:05:45,220 --> 00:05:48,210 So, these three threads, look at them, they are interesting. 91 00:05:48,210 --> 00:05:52,880 They give you a lot of feedback, they also speed up your work tremendously. 92 00:05:52,880 --> 00:05:55,358 Okay, so what's next? Continue enjoying traveling salesman 93 00:05:55,358 --> 00:05:57,633 problem. It's tog also it's time also to start 94 00:05:57,633 --> 00:06:00,897 looking at the LP and the MIP lectures such that you will get on top of those 95 00:06:00,897 --> 00:06:04,840 before you do the warehouse location assignment. 96 00:06:04,840 --> 00:06:08,680 And you know, have fun, I think this is this is going really well. 97 00:06:08,680 --> 00:06:11,452 I think we have a lot of dedicated students we want to bring you know, these 98 00:06:11,452 --> 00:06:14,880 1000 students above that mark that's the goal that we have. 99 00:06:14,880 --> 00:06:17,930 Okay guys, have fun you know, keep going we are very happy.