mersenneforum.org

mersenneforum.org (https://www.mersenneforum.org/index.php)
-   Factoring (https://www.mersenneforum.org/forumdisplay.php?f=19)
-   -   Lucky ECM hit (https://www.mersenneforum.org/showthread.php?t=19746)

Dubslow 2014-10-09 04:41

Lucky ECM hit
 
Running aliquot sequence [url=http://factordb.com/sequences.php?se=1&aq=78816&action=range&fr=1221&to=1221]78816[/url] and found this lucky [URL="http://factordb.com/index.php?id=1100000000715113989&open=ecm"]ECM hit[/URL]:

[code]
10/08/14 23:30:12 v1.34.5 @ Gravemind, [B]current ECM pretesting depth: 30.46[/B]
10/08/14 23:30:12 v1.34.5 @ Gravemind, scheduled 904 curves at B1=1000000 toward [B]target pretesting depth of 35.69[/B]
10/08/14 23:31:12 v1.34.5 @ Gravemind, [B]prp39[/B] = 397014779879110918974351728195016076189 (curve 8 stg2 B1=1000000 sigma=
2353567942 thread=1)
10/08/14 23:31:12 v1.34.5 @ Gravemind, Finished [B]56 curves[/B] using Lenstra ECM method on C116 input, B1=1M, B2=gmp-ecm de
fault
10/08/14 23:31:12 v1.34.5 @ Gravemind, [B]final ECM pretested depth: 30.77[/B]
[/code]
The penultimate factor of the group order is just over 1% from the B1 bound.

It's also lucky that I happened to be watching it at the time, or I wouldn't have noticed.

legendarymudkip 2014-10-19 18:41

[CODE]current ECM pretesting depth: 20.24
scheduled 214 curves at B1=50000 toward target pretesting depth of 25.85
[B]prp31[/B] = 2193059645364365637108057957697 (curve 56 stg2 B1=[B]50000[/B] sigma=3634287944 thread=0)
Finished 56 curves using Lenstra ECM method on C84 input, B1=50K, B2=gmp-ecm default
final ECM pretested depth: 21.55[/CODE]
A similar case on an aliquot sequence I was running.

Batalov 2014-10-19 18:58

If you think 30-ish-digit hits are lucky, I don't know what you will call [URL="http://mersenneforum.org/showpost.php?p=385501&postcount=382"]that one[/URL].

legendarymudkip 2014-10-19 19:10

Lucky doesn't signify lottery chances :razz:


All times are UTC. The time now is 08:43.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.