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Search: Posts Made By: charybdis
Forum: Homework Help 2021-10-15, 16:30
Replies: 8
Views: 233
Posted By charybdis
I can't think of any cases where this would be...

I can't think of any cases where this would be useful for the numbers that we usually run SNFS on. You can't just switch out the linear polynomial for a quadratic one. The solution (as far as it is...
Forum: Homework Help 2021-10-14, 14:37
Replies: 8
Views: 233
Posted By charybdis
It is not an equation. It is a polynomial. An...

It is not an equation. It is a polynomial. An equation implies that two things are being equated. A polynomial does not contain an equals sign.

I'm not sure what you're asking. The linear...
Forum: CADO-NFS 2021-10-13, 00:44
Replies: 3
Views: 150
Posted By charybdis
CADO does use GMP, but if a new GMP version...

CADO does use GMP, but if a new GMP version caused issues I seriously doubt they would be server issues. What CADO revision are you running?
Forum: Aliquot Sequences 2021-10-12, 19:25
Replies: 3,135
Views: 255,087
Posted By charybdis
Happy to leave it for you. While I remember...

Happy to leave it for you.

While I remember - Greg do you have the c220 postprocessing log to hand?
Forum: Aliquot Sequences 2021-10-12, 14:50
Replies: 3,135
Views: 255,087
Posted By charybdis
:bow: Congrats Ryan and Greg on an enormous...

:bow:

Congrats Ryan and Greg on an enormous job! I make that the 7th largest public GNFS ever?

Anyone working the c163 on the next line?
Forum: CADO-NFS 2021-10-10, 12:46
Replies: 2
Views: 190
Posted By charybdis
The way I understand it, "polyselect" performs...

The way I understand it, "polyselect" performs the equivalent of np1 and nps, "sopt" does the equivalent of nps alone, and "polyselect_ropt" is equivalent to npr. The CADO script runs polyselect...
Forum: Msieve 2021-10-09, 00:12
Replies: 185
Views: 52,619
Posted By charybdis
I have a 1.098e-12 that I never bothered to post...

I have a 1.098e-12 that I never bothered to post because (a) it was hardly an improvement and (b) I figured that with no updates for several years people weren't really keeping track of records below...
Forum: NFS@Home 2021-10-07, 23:18
Replies: 82
Views: 9,683
Posted By charybdis
Same here - well spotted Jon. Didn't even look at...

Same here - well spotted Jon. Didn't even look at the job name; the "35" should have set alarm bells ringing.

The cownoise poly generator appears to automatically generate quartics for exponents...
Forum: CADO-NFS 2021-10-07, 17:56
Replies: 70
Views: 13,120
Posted By charybdis
The way I tested this was to look at the CPU-time...

The way I tested this was to look at the CPU-time stats in the logfile ('stats_total_cpu_time') to find ranges that took almost exactly the same length of time to sieve, and then see which of these...
Forum: NFS@Home 2021-10-04, 14:48
Replies: 82
Views: 9,683
Posted By charybdis
Using composite special-q will also lead to a...

Using composite special-q will also lead to a high duplication rate. It's a useful way to squeeze out a few more relations when yield is low due to suboptimal parameters (eg artificially low lpb and...
Forum: NFS@Home 2021-10-04, 13:30
Replies: 82
Views: 9,683
Posted By charybdis
The normalized relations formula is not...

The normalized relations formula is not applicable when composite special-q are being used, as it is based on the premise that special-q have the same frequency as primes.
Forum: NFS@Home 2021-10-03, 12:51
Replies: 82
Views: 9,683
Posted By charybdis
Very nicely done; glad to be wrong about GNFS vs...

Very nicely done; glad to be wrong about GNFS vs SNFS in this case.



Is this normal for the 16e-small queue?
Forum: Aliquot Sequences 2021-10-02, 17:08
Replies: 3,135
Views: 255,087
Posted By charybdis
It can't - the 2^2 guarantees sigma(n) is...

It can't - the 2^2 guarantees sigma(n) is divisible by sigma(2^2) = 7, so the next term which is sigma(n)-n will also be divisible by 7. Similarly the 7 means that sigma(n) will be divisible by 8, so...
Forum: NFS@Home 2021-10-02, 00:46
Replies: 82
Views: 9,683
Posted By charybdis
Aha, good to know. Sorry if I confused anyone. ...

Aha, good to know. Sorry if I confused anyone.

Never mind the parameter choice for the quartic, I'm surprised this isn't obviously better by GNFS. While it isn't a perfect reflection of...
Forum: NFS@Home 2021-10-01, 20:48
Replies: 82
Views: 9,683
Posted By charybdis
This should be lpbr/lpba 34/32 - not 32/34 which...

This should be lpbr/lpba 34/32 - not 32/34 which would be more appropriate for an octic. (the larger the degree the larger the algebraic side)

Msieve is fine with 34-bit large primes; it's the...
Forum: YAFU 2021-09-29, 21:48
Replies: 15
Views: 1,397
Posted By charybdis
The Windows BOINC sievers work fine on octics,...

The Windows BOINC sievers work fine on octics, and the Linux tasks error out. On small jobs like this that isn't an issue. For the 16e v5 queue, which often only sieves one number at a time for...
Forum: YAFU 2021-09-29, 20:23
Replies: 15
Views: 1,397
Posted By charybdis
Octic-280... interesting. Of course this number...

Octic-280... interesting. Of course this number doesn't have a quartic, but there has been a bit of discussion this year about where the quartic/octic crossover might lie, especially with regard to...
Forum: Lounge 2021-09-29, 15:09
Replies: 321
Views: 51,215
Posted By charybdis
The expectation reaches 52 at p=154772617. For...

The expectation reaches 52 at p=154772617. For the exponents that have been tested so far it is pretty close to 51.
Forum: Lounge 2021-09-29, 12:58
Replies: 321
Views: 51,215
Posted By charybdis
I think a lot of the speculation about the...

I think a lot of the speculation about the heuristic being wrong arose from people applying the linear approximation to the heuristic, in which the log(ap) factor in the probability that Mp is prime...
Forum: CADO-NFS 2021-09-28, 12:12
Replies: 14
Views: 665
Posted By charybdis
CADO is refusing to run because it can't find a...

CADO is refusing to run because it can't find a parameter file for a 2-digit number. If you actually put a params file together, you still get various errors, because CADO is not designed to run on...
Forum: Cunningham Tables 2021-09-27, 23:01
Replies: 104
Views: 33,280
Posted By charybdis
I'd say test-sieve each poly with whatever skew...

I'd say test-sieve each poly with whatever skew it came with (ideally these would be consistent i.e. all cownoise or all CADO, but this won't matter) and only try different skews if it's very close...
Forum: Cunningham Tables 2021-09-27, 22:08
Replies: 104
Views: 33,280
Posted By charybdis
The 3.496e-15 poly scores so highly that it ought...

The 3.496e-15 poly scores so highly that it ought to beat all the others as long as the skew selected is vaguely sensible. Cownoise chooses the skew that produces the best Murphy-E score as...
Forum: Miscellaneous Math 2021-09-27, 14:59
Replies: 19
Views: 821
Posted By charybdis
Apologies, yes you have got the squaring in there...

Apologies, yes you have got the squaring in there too. But you're still reinventing the wheel. Let's look at what's actually happening here.

194 = 64*3 + 2, so we know 194^2 = 64^2*3^2 + 2*64*3*2...
Forum: Miscellaneous Math 2021-09-26, 22:48
Replies: 19
Views: 821
Posted By charybdis
You've come up with an incredibly convoluted way...

You've come up with an incredibly convoluted way of reducing numbers modulo 2^n-1. There is, of course, a much faster way, and indeed this calculation can be done very quickly on a computer because...
Forum: Information & Answers 2021-09-26, 14:56
Replies: 58
Views: 8,151
Posted By charybdis
The difficulty of SNFS is determined by the size...

The difficulty of SNFS is determined by the size of the original number, not the composite cofactor, since it's the original number that determines the polynomial. M1217 has 367 digits, so it has...
Showing results 1 to 25 of 492

 
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