20081123, 13:47  #133 
Jan 2005
479 Posts 
While testing my 80M range (520M600M)
I first tried pfgw to 1000 using Karsten's scripts, then sieve it, and tried Karsten's 'highn' script That took about 4 minutes writing time when a prime was found, so it was waaaay too slow :) second,I tried to n=2000 with pfgw, sieved, and then highn'd it, which was way better (30 sec/write). I'm finishing that now as it is quick enough. I think that running pfgw to 2500 or even 3000 is the most efficient. I will test on following ranges what is best (I'll go for 100M ranges then, and will note total time taken. expect an update in about 10 weeks :) ) 
20081123, 14:14  #134 
I quite division it
"Chris"
Feb 2005
England
81D_{16} Posts 

20081124, 11:38  #135 
May 2007
Kansas; USA
19·541 Posts 
I have done some preliminary doublecheck work on the k=500M506M range. After getting primes from Micha for n=100425000, I decided to just run the entire range up to n=1005 to have an n=2 overlap.
Then using the primes for n=100425000 that Micha sent me and my remaining k's after my testing, I was able to determine the k's that should be remaining at n=25K. To my surprise, they are correct as listed by Micha. (No offense! ) I'm just amazed that there are only 8 k's remaining at n=25K for k=500M505M! I did find a few problems with either Micha's testing or Karsten's scripts though. For the range of n=10011004, I found 6 primes that Micha had as remaining when starting the 2nd part of Karsten's automated processing at n=1004 (n=1005 for some k's it seems). What that means is that he effectively "missed" those primes, which could have caused k's to be remaining that weren't. Fortunately all of the k's eventually yielded primes before n=2100. Below are n=10011004 primes that were missed when starting the 2nd part of the automated processing at n=1004 (or n=1005). The prime on the left is the one that I found, the prime on the right in paranthesis is the one found by Micha. 500656302*3^10031 is prime (prime found at n=1300) 502183398*3^10041 is prime (prime found at n=1758) 502572138*3^10021 is prime (prime found at n=1785) 503150118*3^10021 is prime (prime found at n=1909) 505353468*3^10021 is prime (prime found at n=1620) 505663726*3^10011 is prime (prime found at n=2091) Note that the automated process had some n=1004 primes in it so it is very confusing that it did not find the k=502183398 prime at n=1004. My overlap up to n=1005 confirmed the 3 n=1005 primes found by the automated process. Please be careful when making the transition from one part of the automated process to the next. It would be easy to drop a k that had no prime or include a k that already had a prime. In this case, we included 6 k's that already had primes. Chris, please continue your doublecheck process also. Testing to n=1000 is all that I felt I had time for. Your doublecheck process is needed for checking up to n=25K. This kind of detailed checking is needed for a new automated process such as this. Thanks, Gary 
20081124, 21:26  #136 
Jan 2005
479_{10} Posts 
Hmm.. no offense taken :)
I find it troubling that there are some misses though. another thing: I just found out the hard way that doing large ranges just isn't doable. The harddrive thrashes, and just keeps on writing/reading, while the processor is out of work... I will do all the ranges by 10M now :) 
20081125, 03:12  #137  
May 2007
Kansas; USA
19·541 Posts 
Quote:
Since the missing primes are all n=10011004, my impression is that you stopped testing your "1st run" at n=1000 but started testing your "2nd run" at n=1004 with the k's that were remaining at n=1000. Perhaps it was something to do with having to rerun the "2nd run" as a result of only doing the k=500M502M range the 1st time around. Although that still doesn't explain why the 2nd run found 2 primes for n=1004 but missed 1 other prime for n=1004. Can you check where you started and stopped your 2 runs? We need to know if there is a bug in Karsten's process or if it was just a "user error". Gary Last fiddled with by gd_barnes on 20081125 at 03:13 

20081125, 07:12  #138 
Just call me Henry
"David"
Sep 2007
Cambridge (GMT/BST)
5794_{10} Posts 

20081125, 15:32  #139  
I quite division it
"Chris"
Feb 2005
England
31×67 Posts 
Gary, either everyone here thinks you are infallible or nobody reads your posts!
Quote:
I have just confirmed them: Code:
500145402 500968542 501526364 501628284 501947956 502362446 502579034 502598216 502683156 502732374 503092266 503163566 503210228 503449428 503961636 504291412 504632274 I'll stop laughing soon. 

20081125, 16:48  #140 
I quite division it
"Chris"
Feb 2005
England
2077_{10} Posts 
Looks like the joke's on me. lol

20081125, 17:28  #141  
Jan 2005
479 Posts 
Quote:
I have had some very hard working days, so any user error that is possible to make, will most likely be made :) 

20081126, 03:38  #142  
May 2007
Kansas; USA
19·541 Posts 
Quote:
I am infallible. You didn't understand. The # of k's remaining is AFTER removing k's that are divisible by the base that don't need to be searched. Just look at Kenneth's website and you'll see! Divide all the k's by 3. If a k is divisible by 3, subtract 1 and see if it is composite. If so, remove it; if not keep it. In almost all cases, you will remove it because k/3^q is already being searched or already has a prime. Ha, ha, ha. Now I laugh times 3! Gary Edit: I just now saw that you said the "joke's on me". I can delete your posts and this post if you want but I have to admit I couldn't resist getting in a dig on you. BTW, both Kenneth and Max have caught errors on my web pages before. :) Last fiddled with by gd_barnes on 20081126 at 03:41 Reason: edit 

20081126, 14:19  #143 
I quite division it
"Chris"
Feb 2005
England
31×67 Posts 
No, I think my public humilation should stand. It might teach me to keep my big mouth shut!

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