help ~ what's my computer doing!

merlinh · 2004-05-09, 17:52

i've just found this site and joined the search but i have no idea what my computer is actually doing, does someone else know?

my prime 95 window says;
The program will now perform a self-test to make sure the Lucas-Lehmer code is working properly on your computer.
Test 1. 3100 Lucas-Lehmer iterations of M24903681 using 1280K FFT length
Test 2. 3100 Lucas-Lehmer iterations of M24903679 using 1280K FFT length
Test 3. 3100 Lucas-Lehmer iterations of M24092961 using 1280K FFT length
Test 4. 3100 Lucas-Lehmer iterations of M23892959 using 1280K FFT length
Test 5. 3100 Lucas-Lehmer iterations of M23592961 using 1280K FFT length
Test 6. 3100 Lucas-Lehmer iterations of M23592959 using 1280K FFT length
Self-test 1280K passed!
Starting P-1 factoring on M24436903 with B1=370000, B2=370000
P-1 on M24436903 with B1=370000, B2=370000
M24436903 stage 1 is 1.87% complete.

outlnder · 2004-05-09, 20:29

Looks like you are on your way to P-1 factoring your first LL test.

Prime 95 is set up to do a one time test on each FFT range before actually starting the test. That's what it did here. It self-tested the 1280K FFT range to make sure your computer was stable enough to continue running Prime95.

It will do this in every range an exponent is tested.

Welcome to GIMPS and good luck.

smh · 2004-05-09, 21:50

To give a bit more detail.

First thing your computer did was an hour long selftest.

Prime95 is a really cpu/memory intesive program and produces wrong results on crapy hardware. Your pc passed the test so it started working on its first exponent. M24436903. Which means 2^24436903-1. This is a several million digit number which will take quite a while to test for primality, so the program first tries to find numbers that divide this huge number.

Other people have already done trail factoring on this number, which means they tried to divide it by small primes.

Your pc is now doing a P-1 test. Which is another way to find factors. This stage consists of 2 stages. It's doing the first stage now. In your case it won't do a second stage (B1=B2). If your pc has sufficient memory, you might want to change the memory settings in the program so it chooses a higher B2 (which gives you a higher chance of succes).

If the P-1 test is unsuccesful, the program will perform a Lucas Lehmer test. This is a test to determine the primality of the number, which will take most of the time. FYI, that test has to run until 100% before it can tell you if the number is prime or not.

Hope this helps. If not, feel free to ask.

2004-05-09, 17:52	#1
merlinh May 2004 England 2₁₆ Posts	help ~ what's my computer doing! i've just found this site and joined the search but i have no idea what my computer is actually doing, does someone else know? my prime 95 window says; The program will now perform a self-test to make sure the Lucas-Lehmer code is working properly on your computer. Test 1. 3100 Lucas-Lehmer iterations of M24903681 using 1280K FFT length Test 2. 3100 Lucas-Lehmer iterations of M24903679 using 1280K FFT length Test 3. 3100 Lucas-Lehmer iterations of M24092961 using 1280K FFT length Test 4. 3100 Lucas-Lehmer iterations of M23892959 using 1280K FFT length Test 5. 3100 Lucas-Lehmer iterations of M23592961 using 1280K FFT length Test 6. 3100 Lucas-Lehmer iterations of M23592959 using 1280K FFT length Self-test 1280K passed! Starting P-1 factoring on M24436903 with B1=370000, B2=370000 P-1 on M24436903 with B1=370000, B2=370000 M24436903 stage 1 is 1.87% complete.

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2004-05-09, 20:29	#2
outlnder Aug 2002 2·3·53 Posts	Looks like you are on your way to P-1 factoring your first LL test. Prime 95 is set up to do a one time test on each FFT range before actually starting the test. That's what it did here. It self-tested the 1280K FFT range to make sure your computer was stable enough to continue running Prime95. It will do this in every range an exponent is tested. Welcome to GIMPS and good luck.

2004-05-09, 21:50	#3
smh "Sander" Oct 2002 52.345322,5.52471 10010100101₂ Posts	To give a bit more detail. First thing your computer did was an hour long selftest. Prime95 is a really cpu/memory intesive program and produces wrong results on crapy hardware. Your pc passed the test so it started working on its first exponent. M24436903. Which means 2^24436903-1. This is a several million digit number which will take quite a while to test for primality, so the program first tries to find numbers that divide this huge number. Other people have already done trail factoring on this number, which means they tried to divide it by small primes. Your pc is now doing a P-1 test. Which is another way to find factors. This stage consists of 2 stages. It's doing the first stage now. In your case it won't do a second stage (B1=B2). If your pc has sufficient memory, you might want to change the memory settings in the program so it chooses a higher B2 (which gives you a higher chance of succes). If the P-1 test is unsuccesful, the program will perform a Lucas Lehmer test. This is a test to determine the primality of the number, which will take most of the time. FYI, that test has to run until 100% before it can tell you if the number is prime or not. Hope this helps. If not, feel free to ask.