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 2013-03-29, 03:44 #1 ixfd64 Bemusing Prompter     "Danny" Dec 2002 California 1001010011102 Posts How unlucky have I been? I just realized I've completed 218 P-1 assignments without finding a factor. Yikes. Anyone ever had a longer dry spell? Last fiddled with by ixfd64 on 2013-03-29 at 03:46
2013-03-29, 03:48   #2
petrw1
1976 Toyota Corona years forever!

"Wayne"
Nov 2006

23·3·193 Posts

Quote:
 Originally Posted by ixfd64 I just realized I've completed 218 P-1 assignments without finding a factor. Yikes. Anyone ever had a longer dry spell?
About 3 times that many rounds of golf and not a single hole-in-one!

2013-03-29, 04:02   #3
Uncwilly
6809 > 6502

"""""""""""""""""""
Aug 2003
101×103 Posts

954610 Posts

Quote:
 Originally Posted by ixfd64 I just realized I've completed 218 P-1 assignments without finding a factor. Yikes.
Can I guess 48 of the numbers?

2013-03-29, 09:14   #4
Mr. P-1

Jun 2003

7·167 Posts

Quote:
 Originally Posted by ixfd64 I just realized I've completed 218 P-1 assignments without finding a factor. Yikes. Anyone ever had a longer dry spell?
I don't recall how many, but some years ago, I went about 5 months without finding any. I think I was doing about one per day, so that wouldn't be as many as yours.

I recommend you try some torture testing. Perhaps your hardware is beginning to flake. Otherwise just carry on. Every P-1 you do is a P-1 that someone else won't have to do, and which, if they did, would have been done a lot less efficiently that you did it.

 2013-03-29, 12:01 #5 Mini-Geek Account Deleted     "Tim Sorbera" Aug 2006 San Antonio, TX USA 17·251 Posts Assuming an average 3.5% chance of success per test (and assuming I'm calculating correctly), there was only a 1 in ~2400 probability that none of the 218 would result in a factor. You should've expected around 7.8 factors. Either you've been VERY unlucky, or your hardware is unstable. Last fiddled with by Mini-Geek on 2013-03-29 at 12:06
 2013-03-29, 14:17 #6 petrw1 1976 Toyota Corona years forever!     "Wayne" Nov 2006 Saskatchewan, Canada 23·3·193 Posts 126 is my worst In my life I have done 2,925 P-1 (on several PC's). My longest streak was 126 with no factors. But I also had a streak of 3 in a row and 4 out of 5. 182 total factors found: 6.22%
2013-03-29, 16:03   #7
ixfd64
Bemusing Prompter

"Danny"
Dec 2002
California

2·3·397 Posts

Quote:
 Originally Posted by Mini-Geek Assuming an average 3.5% chance of success per test (and assuming I'm calculating correctly), there was only a 1 in ~2400 probability that none of the 218 would result in a factor. You should've expected around 7.8 factors. Either you've been VERY unlucky, or your hardware is unstable.
I doubt the latter is the case, considering most of those results are from three different computers (I have four doing P-1 at the moment).

 2013-03-29, 16:08 #8 Xyzzy     "Mike" Aug 2002 11111110010002 Posts As a test, run an exponent that has a P-1 factor already found?
2013-03-29, 17:45   #9
petrw1
1976 Toyota Corona years forever!

"Wayne"
Nov 2006

23×3×193 Posts

Quote:
 Originally Posted by ixfd64 I doubt the latter is the case, considering most of those results are from three different computers (I have four doing P-1 at the moment).
No offense; just checking:

Doing Stge 1 AND 2?
Enough RAM allocated to give you an estimate of at least 4% or more?

Could be one of the 2 reasons above OR just from your unlucky streak.

Last fiddled with by petrw1 on 2013-03-29 at 17:52

2013-03-29, 18:09   #10
chalsall
If I May

"Chris Halsall"
Sep 2002

2×3×5×11×29 Posts

Quote:
 Originally Posted by Xyzzy As a test, run an exponent that has a P-1 factor already found?
If you want to run some tests, here are ten which had a factor found by P-1'ing. Set your PFactor line to have the "Factored To" value to be no more than the last column.

Code:
+----------+---------------+--------+
| Exponent | BitLevel      | FactTo |
+----------+---------------+--------+
| 54911783 | 58.3215560913 |     58 |
| 58910237 | 64.6313400269 |     64 |
| 58726133 | 65.4111557007 |     65 |
| 52733041 | 68.8312835693 |     68 |
| 51247057 | 70.7599105835 |     70 |
| 48609521 | 70.9801712036 |     70 |
| 52303133 | 71.0078811646 |     71 |
| 48533731 | 71.0444488525 |     71 |
| 47254231 | 71.0491561890 |     71 |
| 50556529 | 71.0697021484 |     71 |
+----------+---------------+--------+

 2013-03-29, 18:18 #11 ATH Einyen     Dec 2003 Denmark 2×7×223 Posts Looking at the lifetime stats on the P-1 top producer page: Top 100 producers have 25,681 successes in 536,894 attempts ~ 4.8% success rate Top 1000 producers have 34,632 successes in 794,810 attempts ~ 4.4% success rate Looking at all the 9,834 producers: 37,309 successes in 842,985 attempts ~ 4.4% success rate Using 4.4% for 218 failed attempts: 0.956^218 ~ 0.0055 % or 1 in 18204. Last fiddled with by ATH on 2013-03-29 at 18:27