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Forum: Factoring 2021-10-19, 13:43
Replies: 60
Views: 5,049
Posted By charybdis
Indeed lambda is applied before the size of the...

Indeed lambda is applied before the size of the cofactor is known exactly - as you're probably aware, some crude but clever approximations are used for log2 during sieving.

I don't know why...
Forum: Factoring 2021-10-19, 10:37
Replies: 60
Views: 5,049
Posted By charybdis
Worth noting here that adding 1 to each mfb may...

Worth noting here that adding 1 to each mfb may do basically nothing if the lambdas are too small. Maybe add 0.05 to each lambda at the same time.
Forum: Factoring 2021-10-18, 22:38
Replies: 60
Views: 5,049
Posted By charybdis
For GNFS it appears to be in the high 160s, so...

For GNFS it appears to be in the high 160s, so there's probably a way to go. CADO will always give higher duplication rates than ggnfs because it sieves below the FB bound.
Forum: Factoring 2021-10-18, 20:51
Replies: 60
Views: 5,049
Posted By charybdis
The E score for this number would be more typical...

The E score for this number would be more typical for GNFS ~c146 (comparison is fine assuming you're still using deg 5) so your lims, lpbs and mfbs may be on the small side. As henryzz alluded to, at...
Forum: Factoring 2021-07-10, 13:34
Replies: 60
Views: 5,049
Posted By charybdis
You can use Murphy-E scores as given by...

You can use Murphy-E scores as given by cownoise/msieve to compare polynomials as long as they have the same degree. Helpfully this is a degree 5 SNFS polynomial, so we can compare it to GNFS...
Forum: Factoring 2021-06-30, 15:52
Replies: 60
Views: 5,049
Posted By charybdis
Change all the Fs to Ls and the -1 at the end to...

Change all the Fs to Ls and the -1 at the end to -25.
Forum: Factoring 2021-06-03, 13:34
Replies: 60
Views: 5,049
Posted By charybdis
Don't think the static Q is the issue here, it's...

Don't think the static Q is the issue here, it's more that you're taking a and b at the edge of the sieving rectangle. The relations are concentrated towards the middle, where a and b, and therefore...
Forum: Factoring 2021-06-03, 11:06
Replies: 60
Views: 5,049
Posted By charybdis
On this number, YAFU test-sieves three...

On this number, YAFU test-sieves three polynomials. For each one, it decides which side it thinks is fastest and tests only that side. I'm suggesting that it should also test algebraic vs rational...
Forum: Factoring 2021-06-02, 23:04
Replies: 60
Views: 5,049
Posted By charybdis
I don't know how you got such a huge difference...

I don't know how you got such a huge difference in the ETAs; CADO can spit out some suspect values early on in the job, and I bet that if you let these jobs run to completion the running times would...
Forum: Factoring 2021-06-01, 16:17
Replies: 60
Views: 5,049
Posted By charybdis
Nicely done! Yes: I...

Nicely done!



Yes:



I suggested sieving on the rational side but YAFU just about prefers algebraic side for this polynomial - for a larger number this would call for test-sieving. k*2^n+1...
Forum: Factoring 2021-06-01, 13:17
Replies: 60
Views: 5,049
Posted By charybdis
The change to rels_wanted was only if you were...

The change to rels_wanted was only if you were using sieving parameters generated by YAFU. As you're using Curtis's file you should keep his rels_wanted. Sorry about the confusion.

Go with what...
Forum: Factoring 2021-06-01, 10:38
Replies: 60
Views: 5,049
Posted By charybdis
2 or 3 significant figures is fine though there's...

2 or 3 significant figures is fine though there's no harm in adding more. It should be OK to omit the coefficients that are zero.



Apologies, I phrased that very badly. 0 is rational and 1 is...
Forum: Factoring 2021-06-01, 02:15
Replies: 60
Views: 5,049
Posted By charybdis
Oh yeah, well remembered, pretty sure CADO still...

Oh yeah, well remembered, pretty sure CADO still needs a skew value. The standard rule for a degree d polynomial is skew = (c0/cd)^(1/d). This is not optimal in general but in real life it's close...
Forum: Factoring 2021-05-31, 19:23
Replies: 60
Views: 5,049
Posted By charybdis
Theoretically, yes. Best to just leave out the...

Theoretically, yes. Best to just leave out the lambdas - they're useful for fine-tuning optimal GNFS parameters, but as we don't really have "optimal SNFS parameters" in the same way, we might as...
Forum: Factoring 2021-05-30, 15:16
Replies: 60
Views: 5,049
Posted By charybdis
Y0 needs to be negative here. The requirement is...

Y0 needs to be negative here. The requirement is that the two polynomials have a common root mod N. The root is x, not -x, so the rational polynomial must be t-x (t is the variable because you've...
Forum: Factoring 2021-05-30, 13:27
Replies: 60
Views: 5,049
Posted By charybdis
YAFU is the fire-and-forget method, or at least...

YAFU is the fire-and-forget method, or at least it should be, because a bug (https://mersenneforum.org/showthread.php?p=579480#post579480) seems to have crept in; hopefully Ben will fix this soon.
...
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