Good enough poly for c155?

[theuser]

Hey!
I'm quite new to factoring and succeded in factoring my first c100 in 2 hours. Next I 'll try to factor an RSA512 number and have serveral questions about this so far:
- I used the GPU/CUDA (GTX 470) msieve version to search for almost 20 hrs for a good poly. As a good poly is important I'm not sure if this one is good enough (quite bad alpha?)

# norm 5.270177e-015 alpha -8.128146 e 2.908e-012 rroots 5
skew: 146477223.70
c0: -335180084494455218943109968023552110721911
c1:  57068905935544771475010526643539380
c2:  617825436536712618776594993
c3: -18360699988098555384
c4: -27540246442
c5:  84
Y0: -2614445829682464845433595048200
Y1:  223601907738811921

I'm using the factmsieve.py script. If i want to use this poly i have to convert it to an *.fb file? Is there any command in msieve to do so?

Thanks for your replys!
theUser

[fivemack]

That seems an entirely decent polynomial to me: the E-value is within the range of ones I've sieved on for 155-digit numbers.

The msieve.fb file is easy to produce from the polynomial:

N {number you're factoring}
R0 value of Y0
R1 value of Y1
A0 value of c0
...
A5 value of c5
SKEW value of skew

and there you go. The tags are in capital letters and there are no colons after them.

[henryzz]

Doesn't factmsieve.py work from a ggnfs poly file? I don't know myself because I still use factmsieve.pl(it works so why change). factmsieve.py was made from factmsieve.pl

[schickel]

Originally Posted by theuser

Hey!
I'm quite new to factoring and succeded in factoring my first c100 in 2 hours. Next I 'll try to factor an RSA512 number and have serveral questions about this so far:

Just FYI, the jump from a c100 to a c155 is much bigger than it sounds. I'm working on a c158 that has been sieving since 9/14 on 6 cores (you're in the same ballpark). (Should be able to start the post-processing tonight after work....)

[theuser]

Thanks, i started sieving yesterday night!

Doesn't factmsieve.py work from a ggnfs poly file?

It does, but it converts/creates a *.poly file from a *.fb file.

Just FYI, the jump from a c100 to a c155 is much bigger than it sounds.

I know that this huge step is not easy to manage, I'm aware of this. But i got enough CPUs to split up the sieving process, so hopefully I'll be done with sieving in 7-8 days...