20060113, 16:09  #254  
Aug 2005
Brazil
2×181 Posts 
Quote:


20060118, 15:01  #255 
May 2005
Brutal Police State, UK
3·41 Posts 
Prime 95 for100M digits prefactor project?
Is it OK to use Prime 95 v 24.14 for factoring 332M exponents on this project,
as Factor_4 doesn't work for me, I just get a stack dump. 
20060119, 18:43  #256 
Mar 2005
Internet; Ukraine, Kiev
627_{8} Posts 
Did you download the correct version of factor4 for your CPU (SSE2 vs. normal)? What does the stack dump say?

20060120, 03:00  #257 
P90 years forever!
Aug 2002
Yeehaw, FL
2·5·7·107 Posts 
The current Prime95 client would factor these numbers to 2^76.
The next prime95 client will factor to 2^74 then try P1 factoring then factor to 2^76. Whether the prime95 client in use at the time these huge numbers are LL tested will have the same breakeven points is an open issue. 
20060120, 15:40  #258  
"Curtis"
Feb 2005
Riverside, CA
3^{4}×59 Posts 
Quote:
LL testing time rises roughly with the square of the exponent, so a power twice as long takes roughly 4 times longer to test. Thus, we should spend 4 times longer trialfactoring a number whose exponent is twice as large as some reference point; 4 times longer is the same as 2 bits higher. GIMPS moves to 68bit factoring at n=28 million. Extrapolating, n=56 million should take 70 bits, 112 million should take 72 (thus the 100M exponent above falls into the 71 "for sure", 72 if you feel like it area), 225 million 74 bits, and our 100M digit project 75 bits. I overestimated in my first post. Project billion, at 10 times larger, would take 81 or 82 bits (as Prime95 pointed out, exact depth depends on the efficiency of the CPU in use/algorithm efficiency at the time an LL test is under consideration for such a number). If we round down slightly in the hopes of more efficient code in the future/wanting to make sure we don't waste work done, we should stop 100M at 75 bits, project billion at 81 bits. Note that Prime95's observation about P1 factoring should give us pause in the 75bit range at that depth, trial factoring may not be most efficient. P1 is beyond the scope of our project, so perhaps a 74bit ceiling for trial factoring should be established? Last fiddled with by VBCurtis on 20060120 at 15:41 

20060120, 19:25  #259  
Mar 2005
Internet; Ukraine, Kiev
11×37 Posts 
Quote:
Quote:
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20060121, 10:14  #260 
May 2005
Brutal Police State, UK
3×41 Posts 
My computer is a rather slow Pentium 233 MMX, with 256 MB of RAM.
It is running Windows 2000 Professional Service Pack 4. The version I have downloaded is factor4_02. As a test, I entered exponent 332193457. The program stopped immediately, and created a file called factor4.exe.stackdump, which says: Exception: STATUS_ILLEGAL_INSTRUCTION at eip=10013A27 eax=53E5645C ebx=00000001 ecx=10030224 edx=10030228 esi=13CCDEB1 edi=52FD071A ebp=C0CFD797 esp=00040774 program=C:\Documents and Settings\Administrator\My Documents\unzipped\factor4_02\factor4.exe, pid 980, thread main cs=001B ds=0023 es=0023 fs=0038 gs=0000 ss=0023 Stack trace: Frame Function Args 67010 [main] factor4 980 handle_exceptions: Exception: STATUS_ACCESS_VIOLATION 77804 [main] factor4 980 handle_exceptions: Error while dumping state (probably corrupted stack)  Prime 95, Thank you for your information. 
20060122, 17:55  #261 
Mar 2005
Internet; Ukraine, Kiev
627_{8} Posts 
How to use Prime95/mprime for 100Mdpp: http://ohmdpp.5gigs.com/prime95.shtml

20060123, 09:44  #262 
Mar 2004
3·13 Posts 
I'd like to continue my current reservation and also reserve
332193431 and 332193457 Thanks Footmaster Last fiddled with by Footmaster on 20060123 at 09:51 
20060123, 17:03  #263 
Mar 2004
3×13 Posts 
M332193937 no factor to 2^66, Wc1: 745BA2A7
M332193887 no factor to 2^66, Wc1: 7463A2A1 M332193913 no factor to 2^66, Wc1: 7460A2A5 I ran these through Prime95 and i plan to take all of the exponents up to at least ^66 Regards Footmaster 
20060123, 19:44  #264  
"Curtis"
Feb 2005
Riverside, CA
3^{4}·59 Posts 
Quote:
Another way to say it is each bit has about the same chance of success, but takes twice as long as the bit that came before. Curtis 

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