Fortunately, Xu Yang always remembered his own work, and he was shocked and did not continue to ask, but quickly devoted himself to the development of parallel computing programs after seeing Chang Haonan's optimization ideas.

Since the parametric modeling, sample point selection, and the establishment of the kriging surrogate model had been completed before this, there was not much work left for Chang Haonan and Xu Yang to complete on site.

Despite this, it took almost 10 hours to fully complete the development and review of the optimization program.

After all, in addition to the optimization of the five independent variables of the three-section wing itself, Chang Haonan also added a flow deflector to make it more difficult for himself.

"Whew-"

After checking the code for the last time, Xu Yang pressed the enter key, submitted the calculation task, and then leaned back in the chair and exhaled a long breath.

The next step is to wait for the results to come out, and then decide whether a separate optimization calculation is required for the design parameters of the flow deflector.

"Your cafeteria here...... Is it still open at night? Chang Haonan looked at the moon outside the window that had risen into the sky, and asked with some hesitation.

From the high-intensity work in the morning to now, he is really a little hungry.

"The big cafeteria is closed, but I can invite you to eat Xiaozao." Xu Yang raised his wrist and glanced at the time, then replied.

"Do you still have a small stove here?"

"Of course, at least half of us are night owls, and the cafeteria is overcrowded in the middle of the night."

Xu Yang said and spread his hair in a bun, and then arranged his hair slowly and methodically:

"It just so happens that I also have some questions about differential evolution algorithms, and I want to ask you."

……

After a while, Chang Haonan, Xu Yang, and Yang Xia sat around a table in the small cafeteria of the Institute of Computing Technology, and the large electric fan next to them whined and blew the wind in this direction, barely bringing a little coolness on a hot summer night.

"I have to admit that this morning, I still thought too much about you, thinking that you were just expanding the scope of differential evolution."

Xu Yang, who left the office area, changed into a medium-sleeved floral shirt, and asked Chang Haonan while stirring the fried noodles in the bowl in front of him with chopsticks:

"But after reading the whole calculation program and explanation, I realized that you have actually fundamentally expanded the theoretical basis of the differential evolution algorithm, can you tell us what you think?"

Chang Haonan didn't answer immediately, but glanced at Yang Xia next to him.

Since the Chinese Academy of Sciences asked Xu Yang to assist him in making calculations, there must be no problem with the latter's level of secrecy.

But after all, there are many people in a place like the cafeteria, and he is not sure if he can discuss the problem for a while.

Xu Yang, who was on the other side, naturally saw the reason for Chang Haonan's hesitation.

"Don't worry, I understand the rules, I will only ask about things related to algorithm theory, not about your specific projects."

At the same time, Yang Xia also nodded slightly, saying that if it was only a theoretical discussion, it would not be secret, and the Institute of Computing Technology itself was also a secret-related unit.

After confirming that there was no problem, Chang Haonan finally opened his mouth:

"As one of the developers of the differential evolution algorithm, you should know that it mainly uses the differences between candidate solutions to generate new individuals, so it has a huge advantage in terms of global search speed and global search ability.

After hearing this answer, Xu Yang raised his head and glanced at Chang Haonan with a somewhat strange look, and after a while, he spoke again:

"Do you want to test my theoretical skills, or do you just want to hear me praise you?"

She didn't give Chang Haonan time to interject and answer, but continued directly:

"The differential evolution algorithm is originally designed to solve continuous optimization problems, and it is an unconstrained optimization algorithm, but you are facing a combinatorial optimization problem with constraints."

"So I've been thinking about what I would have done if I had to face this problem."

In the end, my answer is to use "subtraction" and "addition" based on the continuous essence definition to calculate the difference vector, but this idea is barely feasible, but it lacks an operation method for the characteristics of the combinatorial optimization problem, and a repair operation must be introduced to ensure the feasibility of the candidate solution in the evolutionary process. ”

"But your thinking is completely different, from the perspective of the algorithm itself, optimization, or rather, the design of three new differential optimization algorithms."

"Today I roughly understand the first one, which is based on position, rather than the traditional numerical value-based addition and subtraction operation, and in the intersection stage, a permutation-based intersection operation is introduced to avoid destroying the good structural blocks formed and ensure the rapid convergence of understanding."

"As for the other two, I can only understand one approximation, and I dare even say that even if I show my teacher your calculation program and design instructions, he will not be able to fully understand them in a short period of time."

"How's it going, you're not satisfied with my compliment?"

Xu Yang put the chopsticks at the mouth of the bowl and looked at Chang Haonan playfully:

"In addition, you met me today, and if someone else sees your code without a single comment, it is estimated that you will have to memorize it directly."

"I ......"

The conscience of heaven and earth, Chang Haonan definitely didn't have the two meanings that the other party thought just now.

He just didn't know how far the intelligent algorithm had developed in 1996.

"It's really not convenient to explain this matter at the dinner table, to put it simply, my optimization of the differential evolution algorithm is divided into three stages, corresponding to three different types of engineering application scenarios."

Chang Haonan casually mixed a clove of peeled garlic into the noodles, and then continued to explain:

"First of all, the first one, you have seen some of the key points, but not all, to speed up the evaluation of the solution and further improve the optimization performance, I also designed a local search strategy based on the fast combination heuristic method based on the idle time delta matrix......"

"As for the second algorithm, in order to improve the diversity of PDE populations, avoid unnecessary repeated searches, and jump out of local extremums, the tabu search is combined with the permutation-based discrete differential evolution algorithm......

“……”

Unlike when he lectured on fluid dynamics simulation at Beijing and Hangzhou University, Chang Haonan did not understand the theory of this differential evolution algorithm himself, but just learned it through the system, and it was limited to the three used in the wing optimization process, so although it is not a problem to apply it, it is indeed difficult to explain it in simple terms.

In the end, the two chatted until the staff of the small canteen began to clean up and prepare for work, and Chang Haonan couldn't fully explain it, so he had to say that he would definitely do it next time.

"In short, these things are difficult to explain in a short period of time, if you are interested, when I return to the guest house, I can write you an explanation paper on differential algorithm optimization."

In fact, even if there is no such thing, he is ready to go back and carefully sort out the relevant content of the differential evolution algorithm.

Although the system will only provide knowledge directly related to the project, Chang Haonan himself is not completely a novice, and can draw inferences from others and deepen his understanding through his own learning ability.

And Xu Yang on the other side seemed to be still digesting what he had just heard from Chang Haonan, so he just nodded a little stunned, and only said with some emotion after a while:

"I didn't expect that after a few years of studying abroad, my domestic counterparts not only caught up with the world-class level in theory, but also walked ahead of them in terms of technology application, which can be called far ahead!"

"It seems that I chose to return to China after graduation......

Looking at Xu Yang, whose thinking gradually began to change, Chang Haonan thought for a moment, and finally decided......

Let her go.

╮(╯▽╰)╭

(End of chapter)