20080630, 22:03  #100 
May 2007
Kansas; USA
3·7·491 Posts 
Nice work! I'll review it and reflect it on the web pages within the next week or so. I should preface my prior statement: I hope that no new bases with LARGE conjectures are started in the next few months! It's the largeconjectured bases that take so much time to administer. The smallconjectured bases like this are kind of fun. I did a few of them myself < 32 before starting the project to knock out some easy stuff. Gary 
20080702, 06:55  #101 
Jan 2005
479 Posts 
Gary,
I most certainly agree on having a list of ALL primes, but I tend to disagree (for now at least) for base 3 (or other primes with a huge conjecture). It will take a LOAD of discspace, and we won't be near the end of the conjectures anytime soon. When we are, the primes can all be easily generated again (125050976086 as a conjecture with 1/2 eliminated will need 62525488043 entries, with 10 digits for k, and say on average 1 digit for n so a disc space of 687780368473 bytes uncompressed; say it will get compressed 10fold, you'll need about 68.778.000.000 (68 Gigabyte) storageroom. Hmm...now that I calculated I think we should save them, even now... It's not TOO much after all... (This means I'll have to redo the range upto 100 to 10k, as I couldn't afford to keep those large files on my laptop...) What is your opinion on this matter? 
20080702, 18:39  #102  
May 2007
Kansas; USA
3·7·491 Posts 
Quote:
I wondered if you might chime in about base 3. lol Yeah, I'll make an exception there. I personally have all of the primes stored < 30M with the exception of k<10M that I lost when I was laid off from my job. It was stored on my work laptop and I failed to copy it off. I'll rerun it sometime soon. It shouldn't take long. Here is my opinion: I will trust that you or KEP or whomever runs whatever krange for base 3 will keep all of the primes that you find. I'm a little surprised that you said you couldn't "afford" (I assume you meant space and not cost) to keep the primes files on your laptop. Each k=1M primes file is just under 8 MB so it shouldn't be a problem with most hard drives >= 60 GB these days. For your k=70M range, that'd only be 550 MB. As we close in on testing the entire krange (will WE ever do that, lol?), hopefully there will be a better way to send huge zipped files around the internet and we can deal with it at that point. Heck, I'm even keeping the RESULTS files for now, 200 MB per k=1M! For the k=20M that I have, that's 4 GB. That's crazy though. My laptop has an 80 GB hard drive so that would fill the entire hard drive in k<400M. I'll probably delete those at some point but the primes definitely need to be kept. BTW, I run PFGW by kvalue instead of nvalue on base 3 anyway. It's easiest that way. That way, I don't have to worry about sorting the huge primes files by k. Also, if I have an outage, it's easy to restart PFGW from the k that was left off. If you're processing them by nrange, you can't restart it from the n that was left off. PFGW does not remember the k's that were already eliminated on a restart and it starts searching them all over again. (Yuck!) Gary Last fiddled with by gd_barnes on 20080702 at 18:43 

20080702, 20:13  #103  
Jan 2005
1DF_{16} Posts 
Quote:
(Though both are related to eachother ultimately...) I have kept all the prime > n=10k though (not nearly as much space required for that... I'll rerun them in the future; I'll be running upto n=10k with pfgw, kwise... as in: first k=2, then k=4, then k=6 etc... with the script I've made for pfgw (I think I posted it somewhere...) edit: it was here I'll reserve k=120M to 200M to 10k for sierpinski base 3 now. (as said before, I reckon going to 25k takes too long for a single k) When we have 500k's left it's time again to go upward to 25k. What I think of right now too: is there a way to produce a list of all numbers in the range that can be eliminated? Last fiddled with by michaf on 20080702 at 20:15 Reason: added link 

20080703, 06:11  #104  
May 2007
Kansas; USA
3·7·491 Posts 
Quote:
Your reasoning is dead on! One thing I'll mention: In your (k mod 3^2)=0 list, you state that k=79623216 can be eliminated because it's reduced version has a prime > 2. It does not. If you take it further, it reduces to a kvalue that is still remaining, i.e. 79623216/3^3 = 2949008, which just so happens to be the LOWEST kvalue remaining and one in which Siemelink tested to n=100K. Regardless, k=79623216 still does not need to be tested so there is no problem that I can see in your final list. The list will be added to the web pages shortly. Nice work! Gary 

20080703, 06:25  #105  
May 2007
Kansas; USA
3·7·491 Posts 
Quote:
Hint 1: Take your range of n=120M200M and divide by 3, then divide by 3^2, then divide by 3^3, etc. and look at the k's remaining on the web page for each of those ranges, i.e. n=40M66.667M, 13.333M22.222M, etc. Hint 2: Look at the top10 primes list and multiply each of those by 3, 3^2, 3^3, etc. and see if they fall in your range. Note to myself: At some point, I should expand this to a top25 and then a top50 list for this base. Better yet: I should come up with a list of all primes for n>10K. Base 3 is so huge that I probably should have been keeping many more than 10 primes. The problem is my list of primes for k<10M is gone so I need to rerun it. Hint 3: Check the top5000 site for primes in your krange. Hint 2 should cover a large # of them. Suggestion: Search all even kvalues to n=10K. At that point, use the k's found from your elimination list to eliminate k's before starting n=10K25K. It's far easier to write a PFGW script to just do a step 2 on a huge range then to try to piecemeal out k's to eliminate ahead of time. One way that I knew that your list of k's to be eliminated was accurate was that they encompossed entire ranges of kvalues of k's divisible by 3 that were already remaining with no differences. For example, you had every reduced remaining k from k=16.667M33.333M in your range of k=50M100M with no extras and none missing. That's one thing that I was looking for. I mention this because it directly applies to the kvalues that you could eliminate before searching n=10K25K for your new range of k=120M200M. Gary Last fiddled with by gd_barnes on 20080703 at 06:39 

20080703, 11:04  #106  
Jan 2005
479_{10} Posts 
Quote:
We just need to determine where... 

20080703, 12:47  #107 
Jan 2005
479 Posts 
I'm now testing 120200M for only to n=1k, and am doing about 1M per hour.
1M reduces to about 200 k's. At this rate, the searchspace will be exhausted in 125050 CPUhours which is 'only' 14.3 CPU years; after that, some 125050*200 = 62.5M candidates will remain. (I won't do a complete run through there... I will test all ranges upto 25k first) 
20080703, 20:00  #108 
Jan 2005
479 Posts 
Stopping the script at n=1k is not a good idea....
srfile takes about 3 minutes to eliminate 1 prime found... when stopping at 1k, that are LOADS of primes to be eliminated still... Next run I will try stopping at 5k... 
20080703, 21:50  #109  
May 2007
Kansas; USA
2847_{16} Posts 
Quote:
Ah, good point. lol I should have said it doesn't have a prime above n=2 YET! At least we hope it has one eventually. Last fiddled with by gd_barnes on 20080703 at 21:56 

20080703, 21:58  #110  
May 2007
Kansas; USA
10100001000111_{2} Posts 
Quote:
I think that running PFGW to n=10K on all k's will be the best way to go for large kranges. Then use k's remaining to eliminate k's that you can determine can be elminated that already have found primes or are k's remaining for k / 3^q before starting a sieve for n=10K25K. I actually used PFGW all the way to n=25K in my efforts because I could just start it and forget it. That's great for a few million k but it sux for MANY million k. It was spending 80% of it's total time or more searching k's for n=10K25K. In retrospect, it was rather stupid but I was very busy with administering other efforts so I didn't mind just letting 'er rip and forgetting it. Gary Last fiddled with by gd_barnes on 20080704 at 01:10 

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