20100615, 04:44  #45  
May 2010
499 Posts 
Quote:
Quote:
It then takes 1 hour and 3 minutes to sieve a 1T range to p=160M. 

20100615, 12:09  #46 
Jun 2003
2×3^{4}×29 Posts 

20100615, 21:04  #47 
May 2010
499 Posts 
Actually, I meant 1516 hours, which is 12 hours longer than my original estimate. The time was estimated to be from 7PM  10:30AM, but I accidentally calculated it as 7PM  10:30PM
Last fiddled with by Oddball on 20100615 at 21:04 
20100615, 22:47  #48  
I quite division it
"Chris"
Feb 2005
England
100000011101_{2} Posts 
Clueless.
Quote:
Anyway, the exe runs okay but I got the following compiler messages: Code:
lm(44,19) Hint: Converting the operands to "DWord" before doing the add could prevent overflow errors. lm(82,23) Hint: Converting the operands to "Int64" before doing the multiply could prevent overflow errors. lm(102,23) Hint: Converting the operands to "Int64" before doing the multiply could prevent overflow errors. lm(124,23) Hint: Converting the operands to "Int64" before doing the multiply could prevent overflow errors. lm(205,17) Hint: Converting the operands to "DWord" before doing the add could prevent overflow errors. lm(212,48) Hint: Converting the operands to "DWord" before doing the subtract could prevent overflow errors. lm(218,51) Hint: Converting the operands to "DWord" before doing the subtract could prevent overflow errors. lm(223,18) Hint: Converting the operands to "DWord" before doing the add could prevent overflow errors. lm(225,51) Hint: Converting the operands to "DWord" before doing the subtract could prevent overflow errors. lm(312,35) Hint: Converting the operands to "DWord" before doing the add could prevent overflow errors. Project "lm" successfully built. :) (Windows 7 64bit.) 

20100616, 00:22  #49 
Jun 2003
1001001011010_{2} Posts 

20100616, 00:25  #50 
Jun 2003
2·3^{4}·29 Posts 
Not thinking big enough.
SieveSize and SmallPrimes can be bumped up quite a bit. I have tried SmallPrimes of 60e6 (p~1.2e9), and SieveSize of 6e6, and it runs in under 2hrs. That should save a lot more hours off NewPGen sieving.
Last fiddled with by axn on 20100616 at 00:34 Reason: Sieve size is 6e6 not 6e9 ! 
20100616, 12:49  #51 
I quite division it
"Chris"
Feb 2005
England
31·67 Posts 
axnSieve rocks!
Using SmallPrimes of 60e6 ("p<=1,190,494,759"), and SieveSize of 6e6 as above:
2hr 55m for 1T range on one core of DualCore T4400 laptop. 2.2Ghz, 1Mb L2 cache. Windows 7, 64 bit. Very nice. Uses 1,268,972K of RAM in task manager. As you suggest, I'll compare a sample with NPG's output. 
20100616, 21:30  #52 
I quite division it
"Chris"
Feb 2005
England
31·67 Posts 
axnSieve
SmallPrimes of 60e6, SieveSize of 60e5 produces identical results to NPG over a 0.05T sample. (The only difference was the header where NPG stopped at a P ten less than axnSieve.)
Testing underway for 90e6/90e5, P=1,824,261,409. Looks like 2T will take about 6hr 15m. (Uses 1,833,380KB.) I reached a compiler error at 93e6/93e5 but 92e6/92e5 compiled fine. (I won't go that high though.) With 60e6/60e5 a 1T sieve uses 192Mb in NPG so 2T will fit comfortably, but even with 90e6/90e5 I don't think 3T will be <485Mb. (Hmmm. Might be worth tweaking the program to do 2.5T.) 
20100616, 21:39  #53  
Jun 2003
2·3^{4}·29 Posts 
Quote:
PS: I remember there being a rule saying something like 6 bytes per k. That'd mean 384 MB can handle 64M (=67108864) candidates in fast array mode. 

20100616, 22:04  #54  
Jun 2003
2×3^{4}×29 Posts 
Quote:
However, I am not sure it is worth it. Basically, going from 60e6 (~1.2G) to 90e6 (~1.8G) takes you (6h15)/2  2h55 = 12 min (assuming both numbers are from the same machine). Implementing the memory saving measures will probably introduce a slow down of 1015% (pure speculation). Let's say instead of 3hr7 for a 1T range, it takes 3h30. So the effective delta would be 35 min instead of 12 min. Can NewPGen cover the same range (ie 1.21.8G) in 30 min? I realise that, since 1.8G is already done, the correct analysis should be from 1.8G to _optimal sieve point_. Fine. Can you post some timing for NewPGen to take a 1T (or 2T or whatever) range from p=1.8G to p=3G in increments of 0.2G? That'll give me a clue as to what is a good cutoff point. PS: There is another idea that'll give me a 5x speed improvement. But this involves sieving candidates out of order (technically, residue classes mod 7*11*13). So the candidates will have to be sorted after the sieving step. 

20100616, 22:34  #55 
"Dave"
Sep 2005
UK
2·19·73 Posts 

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