Siheyuan (traditional courtyard house): Starting with the Korean War, returning home to take charge

Lin Jianguo raised his head, his movements slow, as if the bones in his neck had rusted. His eyes were red as if they were filled with sand, and he blinked with an alarmingly low frequency. He stared at He Yuzhu for several seconds before recognizing him. His lips were stuck together, and when he opened them, they twitched as if tearing off a piece of tape that had been stuck on for too long. He opened his mouth, but no sound came out. He cleared his throat and managed to squeeze out a sentence.

"Dean, what brings you here?"

His voice was hoarse, like sandpaper scraping against sheet metal. He Yuzhu didn't answer, but walked to the control panel and looked at the screen. The screen was covered with formulas: tensors, metrics, Green's functions. The bottom line of red text was glaring—the calculation was diverging and couldn't be continued.

"Where is it stuck?"

Lin Jianguo pointed at the error message, his finger lingering on the screen for a moment before retracting it, as if afraid of hurting something. His voice lowered, carrying an indescribable weariness.

"Green's function. The Green's function in curvature spacetime is nonlinear, and existing algorithms can't handle it. It diverges after the third step, and no amount of adjustment helps." He paused, swallowing hard. "Seventeen algorithms. Finite difference, spectral method, finite element method—we've tried them all. None of them converge."

He Yuzhu didn't speak. He stood there, staring at the line of red text for a long time. The fans in the server room hummed, the sound sharper than usual, like something was breathing. There was a faint, burnt smell in the air, not strong, like aging electrical wires, or like plastic softening from being baked.

"How long has the machine been running?"

Lin Jianguo paused, as if he hadn't heard clearly, and only reacted after two seconds. "Three days and three nights. Without stopping."

He Yuzhu turned around and looked at the young technicians. One was asleep, slumped over the table, his face pressed against his arm, a little drool dripping from his mouth. Another was leaning back in his chair, his head tilted to the side, his mouth half-open, snoring intermittently. A third was holding a coffee cup, long since empty, to his lips, like a statue.

"Stop the machine. Let it rest."

Lin Jianguo suddenly raised his head, his lips moving slightly. "Dean, give me a few more days..."

"You should take a break too," He Yuzhu interrupted him. "I'll give you the new algorithm in three days."

Lin Jianguo froze. He stared at He Yuzhu, his eyes bloodshot, with dark circles under them, as if he'd been punched twice. He opened his mouth, wanting to say something, but no words came out. Several seconds later, he finally spoke, his voice weak and unsteady.

"A new algorithm? Where did it come from?"

He Yuzhu didn't answer. He walked to the front of the server rack, stretched out his hand, and pressed the back of his hand against the metal casing. One second, two seconds, and in the third second he pulled back. It was hot. Not the usual warm temperature, but the kind of hot that made the back of his hand turn red. The fan spun faster than usual, its sound shrill, like it was shouting.

He turned around, patted Lin Jianguo on the shoulder, said nothing, and left.

Lin Jianguo stood there, his lips moving as if he wanted to call out to him, but the words didn't come out. He lowered his head, staring at the line of red text for a long time. Then he pressed the shutdown button. The fans slowly stopped, the indicator lights went out, and the server room fell silent—so quiet you could hear your own heartbeat.

The technician, holding an empty coffee cup, was startled awake by the machine shutdown noise. He opened his eyes and looked around blankly. He glanced down at the cup, paused for a moment, then stood up to pour himself some water.

After taking a few steps, I discovered that the thermos was empty.

He stood there, holding the empty cup, unsure whether to put it down or keep walking.

He Yuzhu returned to his office, closed the door, and didn't turn on the light. He sat in the darkness, leaning back in his chair, his eyes closed. Lin Jianguo's face kept flashing through his mind—red eyes, dark circles under his eyes, his lips stuck together and torn open. The young people were asleep on their desks, their coffee cups empty, their thermos flasks empty too.

He opened his eyes and brought up the system interface. The screen lit up in the darkness, its pale blue light illuminating his face. He flipped to the "Mathematics" section and scrolled down several pages. There was a line of text, grayed out, that had never been lit.

Numerical Solution for Curvature Spacetime

[Includes: nonlinear Green's function calculation methods, spatiotemporal metric discretization schemes, parallel algorithm optimization, and convergence proof]

[Redeemable Points: 1,000,000]

He stared at the words, tapping his fingers twice on the table. Twenty million. He still owed thirty-five million points; another twenty million would make it fifty-five million. He sat in the darkness for a long time before clicking "redeem."

The screen flickered.

[Redeem successful. Points consumed: 1,000,000]

[Current total points: -35,000,000 - 20,000,000 = -55,000,000 points]

He retrieved the stack of documents from his system space; it was thick, with the words "Numerical Solution of Curvature Spacetime" printed on the cover. He opened to the first page, which contained dozens of pages of formulas, densely packed together, on the Green's function calculation method. He looked at it for a while, then closed it and wrapped it in kraft paper.

Outside the window, the moon peeked out from behind the clouds and shone on the courtyard wall, casting a grayish glow.

The next afternoon, He Yuzhu went to the Fifth Academy of Aerospace Science and Technology. Lin Jianguo was waiting in the computer room, his hair still messy, but after washing his face, the dark circles under his eyes had faded somewhat. He took the stack of documents, opened the first page, looked at it for a few seconds, and then his fingers paused.

"Dean, this thing..."

He Yuzhu looked at him. "Can it be counted?"

Lin Jianguo lowered his head and continued flipping through the pages. He turned each page slowly, his fingers tracing the formulas as if touching something precious. He paused when he reached the page on parallel algorithm optimization.

"It can be calculated. But the algorithm is too complex, and it takes a long time to calculate once." He looked up at He Yuzhu. "Even if Galaxy Six runs continuously for a month, it might not be able to finish."

He Yuzhu didn't speak. He walked to the server rack and reached out to touch it. It was cool; it had just been turned on. He turned around and looked at Lin Jianguo.

"What if it burns?"

Lin Jianguo thought for a moment. "The 45-nanometer chips at the Shanghai Radio Factory are already in mass production. We'll replace them as soon as they're burned."

Ma Yuejin walked in through the door, carrying an iron box—a prototype fusion battery. He walked to the cabinet, squatted down, touched the casing, stood up, and placed the iron box on the table.

"Dean, I've arranged for someone to be on duty 24 hours a day." He paused. "Burn it and replace it with a new one. One month, until the calculation is complete."

He Yuzhu looked at the metal box. "How's the fusion battery project going over there?"

Ma Yuejin lowered his head, picked up the box, and twirled it in his hand. "Miniaturization is harder than expected. The neutron irradiation problem can't be solved." He looked up and gave a wry smile. "Two years. Another two years."

He Yuzhu didn't say anything. He patted Ma Yuejin on the shoulder and walked out of the computer room.

Ma Yuejin stood in front of the server rack, stuffing the metal box back into his pocket. He called out towards the door.

"Dean, he can't escape."

He Yuzhu did not turn around.

That evening, He Yuzhu sat in his office and took the list out of his drawer. Turning to the page on "Warp Drive," after the words "numerical solution," he added a line: "Lin Jianguo's team worked tirelessly; Galaxy Six operated continuously for a month. Ma Yuejin arranged 24-hour shifts; chips that burned out were replaced."