20030619, 17:43  #1 
Jun 2003
3×7 Posts 
HOW MANY CALCULATIONS AT ONCE??
To complete a result takes poss 4 weeks +,
How many seperate or different prime numbers are tested in this period? It must be more than 1 number?? 1) The counter would continually reset after finding the number was not prime and then go on to the next one, only with prime numbers taking the full time to work out. 2) A computer must be able to calculate several numbers in a month. ??? 
20030619, 17:52  #2  
"Richard B. Woods"
Aug 2002
Wisconsin USA
2^{2}×3×641 Posts 
Re: HOW MANY CALCULATIONS AT ONCE??
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But GIMPS has already tested all the smaller numbers, and the very large ones it's testing now take a long time to test. Which number are you testing? What type and speed is your computer? 

20030619, 18:11  #3  
Dec 2002
Frederick County, MD
562_{8} Posts 
Re: HOW MANY CALCULATIONS AT ONCE??
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20030619, 22:10  #4 
Jun 2003
21_{10} Posts 
I have a 3.06 P IV with 2gb Ram and a fast graphics card. 49.61% through a number in approx 2 weeks.
Does this mean that for instance if the number is "test/3" it completes and moves onto the next?? If it is still running weeks later it is possibly closer to a prime??? These prime number tests really show how unadvanced single computers really are. In ten years time when we have faster machines, the prime numbers will be exponentially larger I guess. 
20030619, 22:13  #5 
Jun 2003
3×7 Posts 
how do you know what number you are testing??? 19463897 is obviously the start, is there any more info on the number I am testing??

20030619, 23:17  #6 
Aug 2002
2·3·29 Posts 
The number you are testing is
2^194638971 which is a faily large number. 
20030619, 23:26  #7 
Aug 2002
Ann Arbor, MI
433_{10} Posts 
some of this stuff should go into an FAQ somewhere......
The number you are testing is actually 2^19463897 1. (edit: go to http://www.mersenne.org/prime5.txt to see what 2^13466917 1 looks like. ) To prove it's prime, you have to do recursive series. If, in this case, the 19463897th term is 0, than 2^19463897 1 is prime. But you have to complete the whole test to figure out whether or not it ends in 0. 
20030619, 23:38  #8  
Aug 2002
2×101 Posts 
Quote:
It takes so long because we are testing numbers that are huge. Back when double checks were still doing 4.5 million range exponents, they took about a week on my 466 Celeron. 

20030620, 03:21  #9  
"Richard B. Woods"
Aug 2002
Wisconsin USA
2^{2}×3×641 Posts 
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19463897 has only 8 digits. 2^194638971, if written out in decimal form, has 5,859,217 digits. The numbers we're working on are so big that in GIMPS discussions we commonly refer to them by just the exponent. So when you see folks write that they're working on "12345679", they really mean they're working on 2^123456791. To avoid confusion, it is customary to write "M" just before the exponent, like "M12345679", to denote that the number under discussion is the Mersenne number 2^123456791, but some folks don't bother with that in forum postings. 

20030620, 12:25  #10 
Jun 2003
2^{5} Posts 
I had a silly idea but I deleted it :)

20030621, 08:40  #11 
Jun 2003
3×7 Posts 
I understand a little better now, thanks.
It is a very big number. "HUGE" If I am working on M19463987, and each of us are working on single exponents of a 5.5 million digit number, how can any individual be responsible for finding a prime, I am sure the ansswer is obvious but I am just missing somthing I guess 
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