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Old 2013-01-21, 19:41   #1
ryanp
 
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Jun 2012
Boulder, CO

2·7·13 Posts
Default Advice for large SNFS jobs?

Hi all,

I'm working on factoring (2801^83-1)/2800 using a modified factmsieve.py -- and yes, I have a cluster available to me... :)

factmsieve tells me at the get-go:

Fri Jan 18 09:58:41 2013 -> Estimated minimum relations needed: 5.53168e+08

I'm able to make it up to about 200M relations with the default parameters (starting at rational q from 238450000, FAMAX = 476900000) before hitting GGNFS' limit: it can't handle special q >= 2^30 - 1.

Does anyone have any advice for what to do with jobs this big? Try to change the sieving window somehow? (And if so -- to what)?

Here's the polynomial I'm using:

Code:
n: 4784427753962229503583191777575386925462640502543527013793934480234680863804447852383959785408791045459809147067083157248015897910382151758867576620242257524246139326208569043470479714282260046673050230392057658284742406595942226610043596316622243579005395853667131475327572196568483
m: 1829715316371090533839726975772594414416841479201
deg: 6
skew: 0
type: snfs
c6: 1
c0: -2801
which gives the factor base:

Code:
N 4784427753962229503583191777575386925462640502543527013793934480234680863804447852383959785408791045459809147067083157248015897910382151758867576620242257524246139326208569043470479714282260046673050230392057658284742406595942226610043596316622243579005395853667131475327572196568483
SKEW 3.75      
A6 1
A0 -2801
R1 1
R0 -1829715316371090533839726975772594414416841479201
FAMAX 476900000
FRMAX 476900000
SALPMAX 4294967296
SRLPMAX 4294967296
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