Look! It's a big one!

akruppa · 2005-11-10, 18:27

Code:

Run 2 out of 52:
Using B1=110000000, B2=680270182898, polynomial Dickson(30), sigma=3001167417
Step 1 took 686315ms
Step 2 took 254074ms
********** Factor found in step 2: 516469933130631687266967194982169414626403685360388146231581267
Found probable prime factor of 63 digits: 516469933130631687266967194982169414626403685360388146231581267
Probable prime cofactor 3398721147883236398400986102209247253337482990178523382057924811844177557035850104125741577569050393864392779989 has 112 digits
Report your potential champion to Richard Brent <rpb@comlab.ox.ac.uk>
(see ftp://ftp.comlab.ox.ac.uk/pub/Docume...ent/champs.txt)

This is a factor of 3,533+. I'll go for a beer now.

Prost,
Alex

Citrix · 2005-11-10, 18:33

congrats!

xilman · 2005-11-10, 19:31

Quote:

Originally Posted by akruppa

Look! It's a big one!

Oooh er! Missus.

Most UK readers will understand that one. Everyone else can look up "Frankie Howerd" in the usual sources.

Anyway, congratulations are due. Don't get too drunk.

Paul

sean · 2005-11-10, 19:47

Congratulations! Maybe it has already been noted, but even the largest ECM factor found last year would no longer make it on to this years top 10!

[I sit on a bouncy ball at work]

akruppa · 2005-11-10, 20:38

Paul Zimmermann computed the group order:

>FindGroupOrder(p,3001167417);

[ <2, 4>, <3, 2>, <5, 1>, <29, 2>, <43, 1>, <131, 1>, <1231, 1>, <9539, 1>,
<88301, 1>, <186247, 1>, <727577, 1>, <1351957, 1>, <3520093, 1>, <10810561, 1>, <20946756331, 1> ]

The factor would even have been found with GMP-ECM 6.0.x with B1=11M due to the Brent-Suyama extension (with the default Dickson(12)).

Alex

trilliwig · 2005-11-10, 23:59

Nice catch, congratulations!

Kosmaj · 2005-11-11, 04:15

Alex congrats on such a large factor

Is this now the second largest factor ever found by ecm?

akruppa · 2005-11-11, 10:19

It's the third largest: there's a p66 by Bruce Dodson and a p64 by K. Aoki & T. Shimoyama.

Alex

Mystwalker · 2005-11-13, 15:34

Congratulations, Alex!

ValerieVonck · 2005-11-13, 21:14

Respect

Phil MjX · 2005-11-14, 10:00

Wow ! congrats !

Sorry to be late but a question : did you use the opteron cluster to find this one, Alex?
I mean, is this still a hope that simple mortals with one or maybe two cpu at home finds large ecm factors ? (I know the answer is yes but a mean of 7300 years to find a c60 with gmp-ecm on my desktop is a bit frustating

)

The situation is the same with gnfs : with a cluster and time, you do a c180-c200. At home, a c120-c130+...

Bye.

Philippe.

2005-11-10, 18:33	#2
Citrix Jun 2003 2×7×113 Posts	congrats!

2005-11-10, 19:47	#4
sean Aug 2004 New Zealand 223 Posts	Congratulations! Maybe it has already been noted, but even the largest ECM factor found last year would no longer make it on to this years top 10! [I sit on a bouncy ball at work]

2005-11-10, 20:38	#5
akruppa "Nancy" Aug 2002 Alexandria 2,467 Posts	Paul Zimmermann computed the group order: >FindGroupOrder(p,3001167417); [ <2, 4>, <3, 2>, <5, 1>, <29, 2>, <43, 1>, <131, 1>, <1231, 1>, <9539, 1>, <88301, 1>, <186247, 1>, <727577, 1>, <1351957, 1>, <3520093, 1>, <10810561, 1>, <20946756331, 1> ] The factor would even have been found with GMP-ECM 6.0.x with B1=11M due to the Brent-Suyama extension (with the default Dickson(12)). Alex

2005-11-10, 23:59	#6
trilliwig Oct 2004 tropical Massachusetts 45₁₆ Posts	Nice catch, congratulations!

2005-11-11, 04:15	#7
Kosmaj Nov 2003 2×1,811 Posts	Alex congrats on such a large factor Is this now the second largest factor ever found by ecm?

2005-11-11, 10:19	#8
akruppa "Nancy" Aug 2002 Alexandria 2,467 Posts	It's the third largest: there's a p66 by Bruce Dodson and a p64 by K. Aoki & T. Shimoyama. Alex

2005-11-13, 15:34	#9
Mystwalker Jul 2004 Potsdam, Germany 3×277 Posts	Congratulations, Alex!

2005-11-13, 21:14	#10
ValerieVonck Mar 2004 Belgium 29² Posts	Respect

2005-11-14, 10:00	#11
Phil MjX Sep 2004 5·37 Posts	Wow ! congrats ! Sorry to be late but a question : did you use the opteron cluster to find this one, Alex? I mean, is this still a hope that simple mortals with one or maybe two cpu at home finds large ecm factors ? (I know the answer is yes but a mean of 7300 years to find a c60 with gmp-ecm on my desktop is a bit frustating ) The situation is the same with gnfs : with a cluster and time, you do a c180-c200. At home, a c120-c130+... Bye. Philippe.