20170424, 03:20  #12 
"Curtis"
Feb 2005
Riverside, CA
4,493 Posts 

20170424, 04:08  #13  
"Anastasia"
Apr 2017
Ukraine
100_{2} Posts 
Quote:
What will you say if I have a supercomputer with 48 cores and 1 Terabyte of RAM? I was trying to check my number on it, but my program used only 1 core :c I don't know how to use multithreading to upgrade my algorithm :c But I think if I do it, I will use 48 cores and it'll be more faster. My friend sais he can help me to use about 200 hundreds cores and 3 terabytes if I will have a good algorithm. 

20170424, 04:40  #14  
"Rashid Naimi"
Oct 2015
Remote to Here/There
2×7×139 Posts 
Quote:
There is a good thread which explains things very clearly. See post number 3 here: http://www.mersenneforum.org/showthread.php?t=22047 All that aside, what kind of a computer program are you using which uses only one core of "about" 200 cores? Is this a windows based system? BTW, welcome to the forum. ETA You could still, (possibly) find factors for your number, as already pointed out to you earlier. Last fiddled with by a1call on 20170424 at 04:46 

20170424, 04:47  #15 
"Anastasia"
Apr 2017
Ukraine
2^{2} Posts 
I using jupyter notebook, algo "isprime" in library (Julia language). Also I work with Big Integer type for this numbers. So this program can easy output such types of numbers (less than 1 min), but it's so hard for it to work with this numbers :c

20170424, 05:00  #16 
"Rashid Naimi"
Oct 2015
Remote to Here/There
2×7×139 Posts 
Well, I am not familiar with Julia language. Just looked it up and looks very interesting.
I am sure one of the gurus here will be able to assist you further shortly. 
20170424, 06:44  #17  
"Serge"
Mar 2008
Phi(4,2^7658614+1)/2
2×4,591 Posts 
Quote:
Let's compare testing prime numbers to building a house. You think you are all set in building your dream house because you have all that is needed: a ton of cement, ten tons of bricks and twenty tons of wood ("48 cores and 1 Terabyte of RAM"). You also have a few tools: a strong power drill, a very long ruler, and a Little Giant MultiPurpose Ladder. (that's "Julia and jupiter notebooks"). ...well, that is not enough! It is not enough because you decided to skip all practicing with small houses (they are too boring, right?)  your house will be 300,000 miles high and the top levels will be reaching the moon. Do you see? You should first get acquainted with the best known practices for best modern house construction, before dreaming about billions, alright? 

20170424, 07:19  #18  
"Anastasia"
Apr 2017
Ukraine
2^{2} Posts 
Quote:
Can I test only numbers that are offered by GIMPS or my own numbers too? Now my computer testing a number offered by GIMPS, can I send a request to GIMPS about testing my number after my computer will have tested it's number? Last fiddled with by Vicodin on 20170424 at 07:20 

20170424, 09:30  #19  
Banned
"Luigi"
Aug 2002
Team Italia
2^{2}·1,193 Posts 
Quote:
You will be more than welcome if you want to close the gaps... Regards. Last fiddled with by ET_ on 20170424 at 09:31 

20170425, 03:44  #20  
Romulan Interpreter
Jun 2011
Thailand
7·1,279 Posts 
Quote:
Last fiddled with by LaurV on 20170425 at 03:44 

20170502, 04:54  #21 
"Harry Willam"
May 2017
USA
2^{2}·5 Posts 
Finding the prime numbers
Checking 1,2,3,4,5,6,7,... all the way up to 46 to see if 47 is prime, we need only test 2,3,5,7...... and 43
Last fiddled with by Harrywill on 20170502 at 04:57 
20170502, 05:11  #22 
Dec 2012
426_{8} Posts 
I'm not sure what prompted your comment, but you need only trial factor up to the floor of the square root of 47: 6 (or 5, since we know that 6 is composite).

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