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Old 2009-02-04, 11:01   #1
fivemack
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Default 109!+1 polynomial search

Let's do the fourth-biggest public GNFS job yet.

EM43 is a bit bigger, but I want to reserve that for running with msieve's new polynomial selection once the parameterisation is sorted out.

Pick a number between zero and 1000 which hasn't been picked before, and post saying which you've picked; as far as I know, you're no more likely to find a good polynomial in any range than in any other. I will use '389' as the example number.

Put the line
Code:
N 144385958320249358220488210246279753379312820313396029159834075622223337844983482099636001195615259277084033387619818092804737714758384244334160217374720000000000000000000000001
into a file called something like bang109.389.data

Obtain (from http://www.mersenneforum.org/showpos...10&postcount=2, or by building them yourself from ggnfs svn) the pol51m0b and pol51opt executables.

Run
Code:
pol51m0b -b bang109.389 -p 8 -n 2e26 -a 38900000 -A 39000000
ie -a 100000X -A 100000(1+X)

which will take about 14 hours on one core2/2400 core (NB it's much quicker for smaller ranges, only about three hours for range 000) and produce a file bang109.389.51.m with between a few hundred and a few thousand lines.

Run
Code:
pol51opt -n 1e26 -N 2e23 -b bang109.389 -e 7.0e-14
which will take between a few hours and a few dozen hours, and will produce a file bang109.389.cand with a widely variable number of lines, consisting of lots of blocks of the form
Code:
BEGIN POLY #skewness 595776.02 norm 2.01e+25 alpha -6.38 Murphy_E 8.73e-14
X5 38911605600
X4 -108887534254406738
X3 169136961931062772632541
X2 25334292654996602951023137471
X1 -15547530941799324358915720760520733
X0 -1511957996366190506345629253321928760525
Y1 25670792597862397667
Y0 -1299837812369852195092370228249064
M 50224823982718742995802804137379401708408180831986072195588571703671977210660885216197454152428679820859446461925150563600872030292505341428504963761763233931421015774088825570
END POLY
These instructions changed on 13 February

If there are any lines beginning 'BEGIN POLY' in bang109.389.cand with a Murphy_E value greater than or equal to 1.00e-13 (your favourite platform's equivalent to

Code:
grep urph bang109.389.cand | sort -g -k 10 | tail
may help), post the whole block here; I'll do test sieving on them all and see which has the largest real-world yield.

Repeat the whole process until March 1st or until you're fed up.

I suspect there's a polynomial with a score better than 1.1e-13 to be found, and every 0.01e-14 improvement in the score will save us several dozen CPU-hours at the sieving stage; we'll start sieving with the best polynomial that's been found by March 1st

Reservations closed 18 February; we have 1.1e-13 polynomials coming out of our ears

Reservations

fivemack 000-009
mdettweiler 010
batalov 011
Jeff Gilchrist 012-019
batalov 020-029
Jeff Gilchrist 030-032
smh 033-035
Jeff Gilchrist 036-039
amphoria 040-042
mdettweiler 043
batalov 044-046
andi47 047
batalov 048-049
sean 050
Jeff Gilchrist 051-059
smh 060-069
amphoria 070-074
smh 075-079
Andi_HB 080-081
sean 082-087
andi47 088
batalov 090-099
bsquared 100-110
bsquared 113-200
amphoria 201-206
sean 207-218
amphoria 224-232
smh 250-254
Jeff Gilchrist 270-299
fivemack 300-399 except 333, 334
Jeff Gilchrist 400-409
Jeff Gilchrist 500-529
Jeff Gilchrist 530-549
Xyzzy 111, 112, 222, 223, 333, 334, 444, 445, 555, 556, 666, 667, 777, 778, 888 and 889.
JoeO 999-1000

Blocks done
fivemack 000-009
mdettweiler 010
batalov 011
Jeff Gilchrist 012-019
batalov 020-029
Jeff Gilchrist 030-032
smh 033-035
Jeff Gilchrist 036-039
amphoria 040-042
mdettweiler 043
batalov 044-046
batalov 048-049
sean 050
Jeff Gilchrist 051-059
smh 60-69
amphoria 70-74
smh 75-79
Andi_HB 080-081
sean 082-087
batalov 090-092
amphoria 201-206
sean 207-212
amphoria 224-229
smh 250-254
Jeff Gilchrist 290-299
fivemack 365-399
Jeff Gilchrist 400-409
Jeff Gilchrist 500-529

Incremental records
Code:
3/2 fivemack        8.56     77918820
4/2 fivemack        8.73  38911605600
5/2 batalov         9.01   2207281680
5/2 fivemack        9.03  38980754880
5/2 batalov         9.39   2050946160
5/2 Jeff Gilchrist  9.51   1955460000
5/2 smh             9.54   3320126820
6/2 batalov        10.6    2601876960
9/2 Jeff Gilchrist 11.3   50353706160
13/2 amphoria      11.5   22748948520

Last fiddled with by fivemack on 2009-02-18 at 10:12 Reason: accumulate many reservations
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Old 2009-02-04, 11:08   #2
Andi47
 
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reserving 47 (look at my nick. )

Last fiddled with by Andi47 on 2009-02-04 at 11:10
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Old 2009-02-04, 12:48   #3
10metreh
 
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How much RAM will this (the poly search) need?
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Old 2009-02-04, 13:15   #4
Andi47
 
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Quote:
Originally Posted by 10metreh View Post
How much RAM will this (the poly search) need?
very little (I think only a few MB) when you are using a recent version of pol51m0b and pol51opt. (there was a huge memory leak in one of these, which was fixed somewhat more than a year ago.)
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Old 2009-02-04, 15:07   #5
mdettweiler
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I'll do 010.
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Old 2009-02-04, 15:09   #6
jasonp
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I'll get msieve v1.40 out as soon as fivemack gives me some parameters for such large jobs; the new poly selection should be run with a leading coefficient perhaps 10-100x smaller than what is being given to pol5. I can also run one or two machines locally with my local sources hacked to allow a monster-size input like this.
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Old 2009-02-04, 18:16   #7
10metreh
 
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I'll take 011 (beware, I will be out quite a bit over the next few days and I have an aliquot sequence, so I may not have my results in for a while).
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Old 2009-02-04, 19:14   #8
sean
 
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I will do 050. Should have more resources for this from next week.
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Old 2009-02-04, 19:25   #9
10metreh
 
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I'm doing my work in 10 sections, doing pol51opt at the end of each one, so I get an idea of what sort of polys I'm getting. Also, I don't want to have to spend too much time at the end doing pol51opt, so I can turn the computer off and save energy.
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Old 2009-02-05, 01:39   #10
mdettweiler
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My computer just got rebooted due to a power flicker in the middle of the pol51opt stage of my range. Is there anything I can do to recover the already-completed work? It had been running the pol51opt stage for at least a couple of hours.
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Old 2009-02-05, 03:15   #11
Batalov
 
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Yes, there's a manual recovery --
http://www.mersenneforum.org/showpos...2&postcount=26

If you didn't redirect the output from the pol51opt then you have to check the last found X5/Y1 values from the .cand file.

I use a script like this one:
Code:
#!/bin/csh
 
set i=25
 
set j=`/bin/echo $i 1 + p |dc`
cp -p P109.389.data P109.0$i.data
nohup nice ./pol51m0b -b P109.0$i -p 8 -n 2e26 -a ${i}00000 -A ${j}00000
nohup nice ./pol51opt -n 1e26 -N 2e23 -b P109.0$i -e 7.0e-14 > P109.0$i.out &
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