NFS filtering error...

Stargate38 · 2016-04-19, 15:39

Can someone please tell me why I'm having trouble factoring this:

2070901086375232525076427110182112190197946724040560217887081294832832281183468746602219497219028189923582071411

I keep getting thousands of "error -11 reading relation xxxxx" lines in nfs.log during the filtering stage. How do I fix this? I don't want to start all over.

The number is from this sequence.

Here's my nfs.job:

Code:

n: 2070901086375232525076427110182112190197946724040560217887081294832832281183468746602219497219028189923582071411
skew: 79263.41
c0: 937866915839812843132381584
c1: -65269251738929456400054
c2: -3995541263443621369
c3: -106346874617468
c4: 756057360
c5: 3672
Y0: -3550187376369013839095
Y1: 12162136159
rlim: 3720000
alim: 3720000
lpbr: 26
lpba: 26
mfbr: 52
mfba: 52
rlambda: 2.5
alambda: 2.5

nfs.fb:

Code:

N 2070901086375232525076427110182112190197946724040560217887081294832832281183468746602219497219028189923582071411
A0 937866915839812843132381584
A1 -65269251738929456400054
A2 -3995541263443621369
A3 -106346874617468
A4 756057360
A5 3672
R0 -3550187376369013839095
R1 12162136159

EDIT: here's my nfs.dat. I've attached my nfs.dat.p to this post. Please tell me what's wrong.

wombatman · 2016-04-19, 17:55

~~You didn't do anything wrong. Sometimes a few of the relations have some error. I've seen -9, -11, and -15, if I recall correctly. Unless you're getting hundreds of the errors, don't sweat it.~~

Edit: Nevermind. I completely missed the "thousands of them" bit. Sorry.

Dubslow · 2016-04-19, 23:15

Given that filtering probably requires a ~few million relations, a ~few thousand errors is still well under 1% of the total number of relations, and shouldn't be a problem. Even 100,000 errors is still recoverable by still doing just a bit more sieving.

What's the filtering log say?

Stargate38 · 2016-04-20, 15:51

Here's my nfs.log (14.2 MB uncompressed). Notice how I kept retrying, to see if it was a bug or not.

chris2be8 · 2016-04-20, 16:53

You would get errors like that if your nfs.dat contains relations from more that 1 job. Every relation from a previous job will generate an error message. And msieve gets confused if the total number of relations it read is much greater than the number of valid unique relations.

You might be able to fix this by deleting the invalid relations from nfs.dat. The last error message is for relation 161019 so try deleting the first 161019 lines from nfs.dat and re-running. MAKE A BACKUP COPY OF nfs.dat FIRST!!

If you still get lots of error -11 messages let it run until it stops producing them. If it fails to factor the number note the number on the last message and delete that many from start of nfs.dat again.

Good luck.

Chris

2016-04-19, 17:55	#2
wombatman I moo ablest echo power! May 2013 1796₁₀ Posts	~~You didn't do anything wrong. Sometimes a few of the relations have some error. I've seen -9, -11, and -15, if I recall correctly. Unless you're getting hundreds of the errors, don't sweat it.~~ Edit: Nevermind. I completely missed the "thousands of them" bit. Sorry. Last fiddled with by wombatman on 2016-04-19 at 17:57

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2016-04-19, 23:15	#3
Dubslow Basketry That Evening! "Bunslow the Bold" Jun 2011 40<A<43 -89<O<-88 3·29·83 Posts	Given that filtering probably requires a ~few million relations, a ~few thousand errors is still well under 1% of the total number of relations, and shouldn't be a problem. Even 100,000 errors is still recoverable by still doing just a bit more sieving. What's the filtering log say?

2016-04-20, 16:53	#5
chris2be8 Sep 2009 2²×587 Posts	You would get errors like that if your nfs.dat contains relations from more that 1 job. Every relation from a previous job will generate an error message. And msieve gets confused if the total number of relations it read is much greater than the number of valid unique relations. You might be able to fix this by deleting the invalid relations from nfs.dat. The last error message is for relation 161019 so try deleting the first 161019 lines from nfs.dat and re-running. MAKE A BACKUP COPY OF nfs.dat FIRST!! If you still get lots of error -11 messages let it run until it stops producing them. If it fails to factor the number note the number on the last message and delete that many from start of nfs.dat again. Good luck. Chris