Trying to find the longest computer program
But how harder? In 1962, the mathematician of Tiber Rado invented a new way to discover this question through what he called the Borgier Business game. To play, start by selecting a certain number of rules – understand all that number LetterHumanity Your goal is to find LetterThe Turing Roll device that runs the longest length before stopping. This device is called Beaver Busy, and the relevant beaver bever number, bb (Letter), The number of steps is required.
Originally, if you want to find a busy beaver for each data type LetterYou just have to do a few things. List all possible items first LetterTuring Machines Roll. Next, use a computer program to simulate running each device. Look for the symptoms of telltale that cars will never stop – for example, many cars fall into infinite repetition rings. Discard all of these non -news devices. Finally, record each other device before stopping a few steps. One with the longest run time is your busy beaver.
In practice, this is difficult. For beginners, the number of possible devices with any new law grows rapidly. The analysis of all of them will be disappointing separately, so you need to write a custom computer program to classify and discard cars. Classification of some machines is easily classified: they either stop quickly or are easily identifiable in infinite rings. But others run for a long time without displaying a clear pattern. For these devices, the problem of stopping it deserves its scary reputation.
The more rules you add, the more computational power you need. But the brutal force is not enough. Some machines work for a long time before stopping it, which is impossible to simulate step by step. You need clever math tricks to measure their implementation.
“Technology advances are definitely helping,” said Shawn Liguki, a long -term Beaver Beaver software engineer and hunter. “But they only help.”
The end of a period
Busy Beaver hunters in the 1990s and 2000s, during the deadlock in BB hunting, began seriously in the BB problem. Among them, Shawon Ligoki and his father Terry were the practical mathematicians who performed their search program on power on powerful computers at the Lawrence Berkeley National Laboratory. In 2007, they found a six -grade Turing machine that broke the record for the longest run: The number of actions he took before stopped was nearly 3,000. This is a huge number with any ordinary measurement. But writing it is not too big. In the 12 -point pen, these 3000 digits will be almost about the cover of a single sheet.
Three years later, a master of Slovak Computer Science, Pavel Kropitz, decided to counter BB (6) Hunt as a Master Thesis Project. He wrote his search program and set it up to run on the background on the 30 computers in a university lab. After a month, he found a device that runs much longer than Ligockis – a new “hero” – in the language of busy hunters.
“I was lucky, because lab people had previously complained about using my CPU and had to retreat a little,” Crropitz wrote in a direct message exchange on the Busy Beaver Challenge Discord server. After another month of search, he set his record with a device that had more than 30,000 figures to run – fail enough to fill about 10 pages.
