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45th Known Mersenne Prime Found?
Posted by
samzenpus
on Wed Aug 27, 2008 08:18 PM
from the really-big-number dept.
from the really-big-number dept.
An anonymous reader writes "The Great Internet Mersenne Prime Search (GIMPS) has apparently discovered a new world-record prime number. A GIMPS client computer reported the number on August 23rd, and verification is currently under way. The verification could take up to two weeks to complete. The last Mersenne prime discovered was over 9.8 million digits long, strongly suggesting that the new value may break the 10 million digit barrier — qualifying for the EFF's $100,000 prize!"
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Firehose:Ten-million-digit prime discovered? by Anonymous Coward
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Link to wikipedia would be nice (Score:5, Informative)
http://en.wikipedia.org/wiki/Mersenne_prime [wikipedia.org]
Fun.
10 million digits (Score:5, Funny)
And you only get 6 digits in prize money? What a rip off. That is only one $digit per 1.67 million prime digits.
Re:10 million digits (Score:5, Funny)
You say that, but at some point someone told me that 1 is a prime number and 2 is as well, so therefore, prime numbers can be one prime number plus 1. Plus, I'm a biologist.
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GPU's? (Score:5, Interesting)
According to their own benchmark pages a newer Core 2 Duo E8500 process in less than 21 days. Just recently I know that password cracking programs were written to use GPU's which dramatically increased the performance. Wouldn't writing code to run this on the GPU's result in even faster processing times?
Re:GPU's? (Score:5, Interesting)
The Lucas-Lehmer test for Mersenne primes consists of repeated multiplication (modulo a fixed large number). Large-integer multiplication is done via floating-point FFT, which is nothing but massive amounts of operations on small numbers. I don't know how FFT implementations for GPUs compare, but intuitively I think they ought to be at least as fast as for CPUs. The primes tested by GIMPS are small enough to fit entirely in GPU memory, so latency doesn't seem like a problem.
(I don't really know much about any of this, so feel free to correct/enlighten me.)
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Just start at infinity... (Score:5, Funny)
And work backwards, that will find the largest much faster than starting at zero.
Prediction (Score:5, Funny)
I predict that the last digit will be... (Score:5, Funny)
...even!
More information please (Score:5, Funny)
The submitter or editor could have at least typed the number into the summary. Lazy bastards.
Re:Forgive my ignorance (Score:5, Funny)
To what use will this long, long prime be put?
Absolutely none whatsoever. That's the beauty of mathematics.
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Re:Forgive my ignorance (Score:5, Insightful)
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Re:Forgive my ignorance (Score:5, Insightful)
"Physics is like sex. Sure, it may give some practical results, but that's not why we do it." - Richard Feynman
I'm guessing it's the same logic at work here.
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Re:Forgive my ignorance (Score:5, Insightful)
I guess some of us have different standards on beauty...
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Re:Forgive my ignorance (Score:5, Funny)
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Re:Forgive my ignorance (Score:5, Funny)
Oblg.
http://xkcd.com/435/ [xkcd.com]
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Re:Forgive my ignorance (Score:5, Informative)
From the GIMPS website:
Finding new Mersenne primes is not likely to be of any immediate practical value. This search is primarily a recreational pursuit. However, the search for Mersenne primes has proved useful in development of new algorithms, testing computer hardware, and interesting young students in math.
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Re:Forgive my ignorance (Score:5, Informative)
But when it comes to primes in the 10 million digit range (I couldn't even guess how many bits you would require for a number that large)
About 33 million bits ( ln(10)/ln(2) = 3.3219 ) or 4MB.
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Re:Forgive my ignorance (Score:5, Insightful)
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Re:Forgive my ignorance (Score:5, Funny)
...
(Random interviews)
Q: What happened when you participated in the GIMPS project?
A: Ah.. It got bigger.
Q: And you're not embarassed to say that?
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Re:I dont understand why this is important (Score:5, Funny)
...he asks on slashdot.
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Re:I dont understand why this is important (Score:5, Funny)
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Because (Score:5, Insightful)
You shouldn't think like that. Just think about your question, seriously. Whatever we do is pointless and useless and everything will be destroyed eventually through the heat death of the universe.
That being said, all that is important is that you have fun doing whatever you do. Believe it or not, some people really dig maths. Also, it's one more thing the species knows.
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Re:I dont understand why this is important (Score:5, Funny)
Because doing it by hand is a real bitch and a half. Doing it by hand in moon or candle light sucks worse, I must add.
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Re:Well, I just beat them! (Score:5, Informative)
You seem to misunderstand the meaning of prime [wikipedia.org]. Either that, or you're a horrible comedian. In either case, 77 isn't prime, and neither is 77777777.
However, even if a string of 7's were prime, that may not be enough. As stated previously, if n = 2^x - 1 is prime, then x must be prime. However, the converse is not true. That is, x being prime does not guarantee that n is prime. E.g., if x = 11, then n = 2^{11} - 1 = 2047 = 23 x 89.
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Re:I guess there's some room to ask... (Score:5, Informative)
FTFA:
Still, it's not hard to think of some more, well, "electronic frontier-ish" applications for that kind of money. The FPGA-based DES keysearch engine they built a few years back was cool. OTOH, this Mersenne prime business just sounds like they're paying for something that will become trivial soon enough anyway.
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