The Greek mathematician Euclid may have proved an infinite number of prime numbers around 300 BC. But recently, it was the British mathematician Christian Lawson Perfect who invented the computer game “Is this a prime number?”
Released five years ago, the game exceeded 3 million trials on July 16th. That is, after a surge of about 100,000 attempts in a Hacker News post, it reached 2,999,999 runs.
The purpose of this game is to classify as many numbers as possible into “prime” or “non-prime” in 60 seconds (Lawson-Perfect was first on the math blog The Aperiodical, where he is the founder and editor. As explained).
A prime number is an integer with exactly two divisors, 1 and itself.
“It’s very simple, but annoyingly difficult,” says Lawson Perfect, who works in the e-learning unit of Newcastle University’s Faculty of Mathematics and Statistics. He created the game in his spare time and proved useful at work. Lawson-Perfect creates e-assessment software (a system for assessing learning). “The system I create is designed to randomly generate math questions and receive answers from students, which automatically mark them and provide feedback,” he says. I will. “A prime game can be considered a kind of assessment” — he used it when conducting outreach sessions at school.
He made the game a bit easier with keyboard shortcuts (y and n keys click the corresponding yes-no button on the screen) to save mouse movement time.
Prime number check algorithm
Prime numbers are practical in computing, such as error correction code and encryption. However, while prime factorization is difficult (and therefore its value in cryptography), prime factoring is easy, even in tricky cases. Fields Medal-winning German mathematician Alexander Grothendieck is notorious for mistaken 57 for a prime number (“Grotendique prime number”). Lawson-Perfect analyzed the game’s data and found that various numbers indicate a particular “Grothendieckyness”. 51 was most often mistaken for a prime number, followed by 57, 87, 91, 119, and 133. Lawson-Perfect’s nemesis (he also devised a convenient primality test service: https: //isthisprime.com/2).
The minimum algorithm for checking the prime numbers of numbers is trial division. Divide the number by all the numbers up to the square root (the product of two numbers greater than the square root is greater than the number in question).
However, this simple method is not very efficient and no other method has been devised over the centuries. As the German mathematician Carl Friedrich Gauss observed in 1801, “even the most timeless calculator requires unbearable effort.”
The game-coded algorithm Lawson-Perfect is called the Miller-Rabin Primitiveness Test (which is very efficient, but based on the non-iron-walled 17th-century method “Fermat’s Little Theorem”. Masu). The Miller-Rabin test works surprisingly well. As far as Lawson Perfect is concerned, it’s “basically magic”. “I’m not sure how it works, but I’m sure we can take the time to dig deeper,” he says.
The test uses randomness, so it produces probabilistic results. That sometimes means that the test lies. “You may find a scammer who is a composite number that is about to pass as a prime number,” says Carl Pomerance, a mathematician and book co-author at Dartmouth College. Prime number: Computational point of view.. However, the test is “quite safe” because the chances of a scammer evading the clever checking mechanism of the algorithm are probably one trillionth.
But as far as clever primality testing algorithms are concerned, the Miller-Rabin test is “the tip of the iceberg,” Pomerance says. In particular, 19 years ago, three computer scientists, Manindra Agrawar, Nirajukayal, and Nightin Saxena, all announced the AKS prime number test at the Indian Institute of Technology, Kanpur (also based on Fermat’s method). Masu). The numbers are prime numbers, there is no randomization, and they are (at least theoretically) impressive speeds. Unfortunately, AKS testing isn’t useful for practical purposes because it’s not always fast in theory.
Informal world record
However, practicality is not always important. From time to time, Lawson-Perfect receives emails from people who want to share their high scores in the game. Recently, the player reported a prime number of 60 in 60 seconds, but the record is likely to be 127 (Lawson-Perfect does not track high scores. He is computer-aided to generate spikes in the data. In an attempt, I know there are some scammers.)
The 127 score was achieved by Ravi Fernando, a graduate student in mathematics at the University of California, Berkeley. He posted the results in July 2020. This is still his personal best and he considers it an “unofficial world record”.
Fernando hasn’t played much of the game with default settings since last summer, but he tried customized settings, chose a larger number and allowed a longer time limit. He won 240 with a 5 minute limit. “This required a lot of guessing, as the numbers were in the high four-digit range and only memorized prime numbers were as low as 3,000,” he says. “I think some people still argue that it’s excessive.”
Fernando’s work is algebraic geometry and contains some prime numbers. But he states, “My research is more about why I quit the game than why I started it” (he got his PhD in 2014). Moreover, he thinks it will be very difficult to beat 127. “I feel right to stay on the record of prime numbers,” he said.
Is this number a prime number? There is a game for that.
Google no longer allowing 'Sugar dating' apps in the Play Store – MobileSyrup
Google has changed some of the language in the Play Store’s guidelines to prohibit ‘Sugar Dating’ apps starting on September 1st.
If you’re unfamiliar with the world of Sugar Dating apps, they typically facilitate meetups and relationships between older, wealthier individuals (sugar daddies) and younger, far less financially well-off partners. However, Google pulling these niche apps from the Play Store obviously won’t stop unique relationships like this from happening.
The new rule change specifically says that the Play Store now prohibits “compensated sexual relationships,” as first reported by Android Police. That said, it’s easy to make the argument that a lot of these apps don’t directly encourage sexual relationships and instead just market themselves as a discreet way to meet a partner for this special arrangement.
Beyond the above change, Google also says that it will soon start deleting inactive developer accounts.
Via: Android Police
PlayStation 5 SSD upgrades are finally enabled for beta testers – Engadget
As expected, Sony is gradually opening up access to the PS5’s empty M.2 expansion slot. Starting today, a new system software update gives beta users in the US, Canada and parts of Europe the ability to boost local storage with select SSD drives. But, the process isn’t as straightforward as previous reports suggested.
We already knew the required read speeds would be 5,500MB/s or higher, which limits you to PCIe Gen4 SSDs. Of course, there are plenty of drives that can manage that: The Samsung 980 Pro, Western Digital SN850, Corsair Force MP600, Seagate Firecuda 530, Sabrent Rocket 4 Plus, to name a few.
To make things more complicated, Sony says that you’ll also need to take into account the PS5’s cooling mechanism. That means you can either attach a heatsink to your SSD, either in a single- or double-sided format, or purchase a compatible SSD with the cooling structure built-in. But, even then, it needs to be the right-sized heatsink that matches the required dimensions. The total size including the cooling structure needs to be smaller than 110mm (L) x 25mm (W) x 11.25mm (H) or, in inches, smaller than 4.33in (L) x 0.984 in (W) x 0.442in (H).
Basically, you can forget just popping the cover and slotting in just any Gen 4 SSD. For instance, the Corsair Force MP600 has a heatsink which is too high to fit (though you can purchase it without one and use your own thermal solution). Whereas the WD Black SN850 heatsink should be fine.
Beyond the M.2 SSD support, the PS5 beta software also includes additional software and improvements. Among them is 3D audio support for built-in TV speakers that can boost sound by measuring the acoustics of a room using the DualSense controller. You can switch it on or off from the sound menu in the console’s system settings. What’s more there are a bunch of control customization options in the Control Centre. Here, the Game Base will also let you message friends and parties and see how many friends are online.
While PS4 and PS5 games will also be labeled accordingly and appear separately in the home screen and game library. The update also packs a trophy tracker for quick access to up to five trophies per game via the Control Center, the option to pick between 720p and 1080p on PlayStation Now and the ability to enable automatic video clips in challenges for high scores. The software update is also rolling out in Japan, UK, Germany, and France.
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Google is kicking ‘sugar dating’ apps out of the Play Store – The Verge
“Sugar dating” apps will not be allowed on the Android Play Store from September 1st, Google has announced as part of a series of policy changes for the platform. The change, which was first reported by Android Police, specifically prohibits apps relating to “compensated sexual relationships.” Other changes coming to the platform include a new crackdown on inactive developer accounts, Google says.
Traditionally, sugar dating relationships involve older, wealthier individuals dating and showering younger partners with gifts. As Android Police notes, there’s no shortage of apps on the Play Store designed around setting up “sugar daddy” relationships. None of them explicitly say that older men are expected to compensate younger women for their affection, but many emphasize the wealth of the men on their services.
Google’s Play Store policies already prohibit apps that promote “services that may be interpreted as providing sexual acts in exchange for compensation.” But the updated wording expands this definition to explicitly include “compensated dating or sexual arrangements where one participant is expected or implied to provide money, gifts or financial support to another participant (‘sugar dating’).”
Google’s announcement doesn’t explicitly say why the apps are being banned now. But it comes amidst a crackdown on online sex work by platforms following the introduction of the FOSTA-SESTA legislation in the US in 2018, which removes Section 230 protections for content that “promotes or facilitates prostitution.” A representative from Google did not immediately respond to a request for comment.
Beyond the dating app rule changes, the search giant is also introducing a new policy which will see it delete developer accounts if they’ve remained inactive for a year. Google says it will make exceptions for accounts behind apps with over a thousand installs or with recent in-app purchases, but if a developer hasn’t uploaded an app or signed into the Google Play Console over the course of 12 months, their account is at risk of deletion. In a video outlining the change, Google says it will notify developers of an impending deletion 60, 30, and 7 days before it takes place.
The policy updates also offer more information on Google’s previously announced changes regarding Play Store spam and opting-out of the use of advertising IDs. It’s updating its store listings and promotion policy on September 29 to ban “spam text and graphics in app titles, icons and developer names” and its ads policy is being updated to reflect the advertising ID changes on October 4th.
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