20081130, 14:46  #1 
Nov 2008
Rosenheim, Germany
2^{3}×3 Posts 
Double check LL test faster than first run test
Why is a double check LL test about twice as fast than a first run LL test?
As far as I understood LL testing the number of iterations has to be the same for both kinds of LL tests. Is it because a first run LL test does some intermediate error detecting, which a double check leaves out? What else could it be to make a double check faster then a first run check? 
20081130, 15:57  #2  
Jun 2003
2^{3}·5·127 Posts 
Quote:
However, at any given point in time, the exponents given out for first time testing will be much bigger than the ones handed out for doublecheck. Does that answer your question? 

20081201, 01:14  #3  
"Richard B. Woods"
Aug 2002
Wisconsin USA
2^{2}·3·641 Posts 
Quote:
If what you're comparing is the elapsed time taken by a DC now to the elapsed time taken for the first LL test back when it was first tested, consider that the average computer used by GIMPS participants has gotten faster over time. So the (perhaps) 2.66 GHz system that does the DC may do so in half the time needed by the (perhaps) 1200 MHz system that did the first test. Last fiddled with by cheesehead on 20081201 at 01:16 

20081203, 15:12  #4  
"GIMFS"
Sep 2002
Oeiras, Portugal
3×491 Posts 
Quote:


Thread Tools  
Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
A (new) old, (faster) slower mersenne(primality) PRP test  boldi  Miscellaneous Math  74  20140417 07:16 
LL test successfully completes DoubleCheck of M53137907  TheMawn  PrimeNet  12  20131117 12:51 
Faster LLtest Bounty Questions  __HRB__  Information & Answers  6  20091004 19:37 
A primality test for Fermat numbers faster than Pépin's test ?  T.Rex  Math  0  20041026 21:37 
will searching for factors sometimes be faster than LL test?  ixfd64  Math  3  20031016 22:15 