Chapter 296 Combining Theory with Practice
Of course, Chang Haonan also knew that the godfather mentioned by the other three people did not actually mean the same thing as the godfather in the mafia movie.
In a religious context, it refers to a person who is given a Christian name when he is baptized and promises to undertake his religious education.
The general meaning is that although the two Berkeley professors gave life to the DE algorithm, Chang Haonan and Xu Yang were the ones who gave the DE algorithm the soul.
Considering that few Chinese people would speak in this way, what the other party said should still have a certain degree of credibility.
For Chang Haonan, it is also a good thing to make a name for himself in the fields of engineering theory or algorithms that have nothing to do with confidential projects, which is equivalent to giving him an excellent disguise.
Truth and falsehood are the secrets of confidentiality.
Otherwise, you, a person who has done nothing on the surface, will jump up in status like a rocket. It will not be difficult for someone with a little bit of brains to figure out the reason.
At this time, the files in the floppy disk were also read.
Chang Haonan opened one of them.
"This is the algorithm from Princeton University that won the first place in last year's ICEO competition. The file below is from Kyoto University that won the second place. Since Nagoya University did not participate, they were considered last year's host. These two schools will also participate in the second place this year. It should be our main competitor."
Ling Zhi introduced it at the right time.
"First place...let me take a look."
Chang Haonan opened the first program file inside.
“These two algorithms are indeed very high in optimization efficiency. Last month we used the optimized DE algorithm to improve the efficiency of these five test functions. Although it is lower than last year’s third place result, I have made great progress, but I still can’t compete with them, so I thought I’d trouble you to see if there is any further way.”
Suga Feian said and picked out another one from the floppy disk box:
“This is the result of our design.”
“Don’t worry, let’s take a look at theirs first to see if they can compare. DE is so much faster, and it is quite capable.”
In fact, Chang Haonan was a little surprised when he heard that the differential evolution algorithm only came in third place.
Even before he made improvements and optimizations, the efficiency of DE should in most cases exceed the simulated annealing algorithm that was more popular in this era and the genetic algorithm that was about to become popular in the original timeline.
Considering that the test functions we just looked at are all normal, there is nothing weird about them.
Winning only third place is either because the contestant is not good at studying, or there are other reasons——
If there was such a powerful algorithm, it would have become famous in the academic world.
Because the competition time was limited and the test function was not complicated, Chang Haonan finished reading it in no time.
Of course, normally after reading it, the key parts need to be analyzed and tested, but with his current theoretical level close to LV3, he can save the effort of the previous step to a large extent.
"This thing..."
Chang Haonan frowned and first tried to run the Michalewiczs function in the test question.
It is a relatively uncommon kind of benchmark function, at least in this era, because it acts as a single-objective optimization function, containing several local minima and plane regions, in which all z The values are almost equal, which is not friendly to most algorithms.
The results were very good indeed.
“We have tried several methods, but we can’t achieve such high efficiency. You can run the fifth test function again, and the results are even more exaggerated. Therefore, in the past year, some people have always suspected that these two A group cheated in the test. About last week, the organizers were forced to release all relevant documents. ”
Song Tingyu, who had not spoken just now, said in a hoarse voice.
This also explains why they insist on choosing DE even though they know there are more efficient algorithms.
It’s not because they are admirers of the DE algorithm, but they always thought others were cheating.
But no matter what, their choice was correct.
Because Chang Haonan has understood the little tricks played by the other party.
Compared with suspected cheating and real cheating, it is still a little bit less interesting after all.
"No need, I probably understand what they did."
As he spoke, he opened the second-ranked file and browsed it faster than before.
“Huh?” Lin Zhi’s surprised voice was just halfway out, and she quickly covered her mouth.
They originally planned to come over today and hand the things over to Chang Haonan, and then go back and wait for news for a few days.
I was already ready to take out the gifts and leave.
The result came out on the spot?
“As long as we change the testing method, these two algorithms will be revealed.”
Chang Haonan moved his body and began to build a new mathematical model.
Minf(r,n)=-∏(i=1,m)R(ni)
s.t.g1(r,n),g2(r,n),g3(r,n)
0≤ri≤1, ni∈Z+, 1≤i≤m...
Although they have no background and only have a few broad mathematical formulas, the three of them are worthy of being selected by Yan to participate in international competitions. Among the people, Suga Feian quickly saw the practical problems corresponding to this model:
“This should be a reliability redundancy calculation for a series system?”
Chang Haonan has not even written annotations of the physical quantities represented by each symbol, so it can still be seen. On the one hand, it shows that his mind is really fast, and on the other hand, it also shows that he must have done a lot of homework in the past.
Physics is not pure mathematics. No matter how smart a person is, he cannot see through a physical problem that he has never encountered before.
"Yes, but don't underestimate this simple series system."
Now that they understand it, Chang Haonan is happy to save the trouble of explanation and runs the first algorithm After starting to optimize, he nodded and replied:
“There are many complex equipment, such as the over-protection system of gas turbines or internal combustion engines, which correspond to this model. How to extract as much as possible without affecting the safety of the system? Equipment potential and compression redundancy have become the optimization goals of engineers.”
“In the past, this matter could only be accomplished with experience. Therefore, giants such as Siemens, Mitsubishi Heavy Industries, General Electric, and Ansaldo entered the industry earlier and accumulated richer data and experience. Even with the same skills, With technologically advanced hardware equipment, their unit performance indicators are also much better, which brings them more customers, which in turn provides them with more feedback data, forming a virtuous cycle. Therefore, under this model, later People will never be able to surpass them. ”
“But with the efforts of algorithm engineers like us, this type of control problems have gradually begun to escape the realm of pure experience in recent years, and some theoretical guidance can be obtained to allow control. The accelerated development efficiency of the system gives us countries that have not caught up with the industrial revolution the possibility of catching up.”
In fact, what Chang Haonan said is exactly what he has been doing in the past year. Things——
Not only through his forward-looking vision, but also through technical means to improve the efficiency of scientific research, so that limited funds can play a greater role than others.
After hearing these words, the three people next to them were startled at the same time, and then showed different expressions, but they were all obviously thinking.
In the late 1990s, the computer major in China was prosperous for a few years, but the foundation was shaky. During this period, the popularity of the accounting major was quite blind. The real first-mover bonus period was already in the early 1990s. It was in the past, and the computer industry hadn't really developed yet.
As a result, these students graduated just in time for the collapse of the Internet bubble, and their encounter was almost similar to the group of people who studied biology at the beginning of the 21st century after listening to the nonsense that "the 21st century is the century of biology."
Except for a few big guys, most people will not be able to survive the industry explosion more than ten years later, and have already changed careers.
When entering school under this background, even undergraduates from a school like Yan University may not actually know the use of what they are learning. Many people are simply used to studying hard, or do not use it at all. I studied hard and got a very high score, and then I chose the major with the highest score.
After all, even in the information age more than twenty years later, college entrance examination candidates’ understanding of college majors is still low enough for college entrance examination registration and career planning to become an independent industry, let alone now.
The three of them were actually just sophomore undergraduates, and had not seriously considered issues such as the application of what they had learned before.
Now that I heard Chang Haonan say this, I really felt something for the first time.
While several people were talking, the optimization algorithm running on the computer also came to an end.
But unlike the previous times, it didn’t really output anything.
“There is no need to continue.”
Chang Haonan stopped the program and opened the log file, and quickly found the crux:
“There is a problem with the method of handling constraints, so there is no way to converge, and no valid solution will be output no matter how hard I run it.”
Three faces of shock.jpg
“Look, although these two functions cannot be considered cheating, they actually took advantage of the competition system. The first-place algorithm is only suitable for measurable competition verification. The function cannot be called a general optimization algorithm at all. It has almost no ability to solve complex practical problems. The second place is slightly better, but it needs to calculate the Latin square and is not suitable for situations with too many parameters. It also has great limitations. In other words In other words, the top two are test-taking algorithms that are completely designed for competition."
Chang Haonan analyzed:
"Of course, from the perspective of competition, general algorithms are not more noble than them, but personally, I still hope that the development of algorithmic science can be closer to the actual application level, and..."
Speaking of which He hesitated for a moment, because the following content was indeed his inference, but he finally said it:
“And based on your description, I estimate that this competition may target this kind of behavior. Add some restrictions, such as adding a non-standard model or function to the test process."
"..."
In short, Chang Haonan became the last one in the laboratory that night. People who leave.
(End of this chapter)