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Posts by bdodson*

1) Message boards : News : 3,766+ factored (Message 1509)
Posted 18 Mar 2015 by bdodson*
3,766+ has been factored. It is the product of 66-digit, 75-digit, and 76-digit prime numbers. This is a new Cunningham project champion for GNFS. Let's now set a new record with 3,697+!

In lieu of a much needed status update, 3,697+ was completed
and reported to the Cunningham site during February as c221=p67*p76*p78

6319 3, 697+ c221 2430596119059914710337969915407030131984125918638366960356417238051.
c154 NFS@Home gnfs

6320 3, 697+ c154 7294369040882787305640699831446454559916572630347346447156318424089217886547.
p78 NFS@Home gnfs

as compared with

6269 3, 766+ c216
c151 NFS@Home gnfs

6270 3, 766+ c151 626943698188540315697357582114234580866611225002057825604732642929274209337.
p76 NFS@Home gnfs

for the previous record.

That was


for the smallest factor. Current ecm-pretesting is fairly reliably
finding p65's, using standards set in pretests for these nfs@Home
gnfs's at c216, c221. Seems like one of these might have been found,
with a bit more luck.

Cunningham numbers currently reserved for nfs@Home include

206 2,2218M 91029105429371... 20.6t55=.8t65; reserv nfs@H, gnfs
208 10, 359- 47097509129120... 24.4t55=t65; reserv nfs@H, gnfs

If I recall, 3t60 =c. 15t55 was applied to these two record gnfs's.
I was muttering at the time that adding an additional 2t60 to a
completed 3t60 (for a c. t65) seemed too likely to be unproductive;
but I've since gotten used to it (more or less!).

-bdodson* (still 4th in total sieving creds; maybe 4th in ecm?
after four consecutive records)
2) Message boards : Questions/Problems/Bugs : Work to do (Message 1085)
Posted 28 Jan 2013 by bdodson*
That's a possibility, but not during this grant year. I proposed a fairly aggressive schedule, so I don't want to take computers away from those numbers. Following 2,1049+, I've proposed three GNFS factorizations of 202, 207, and 212 digits, presuming they survive ECM pretesting.

As I was remarking over on mersenneforum
Dec 28 09:43 dec27-cu26987-p60up-5t55-10M770
Jan  1 11:21  dec31-cu25200-p60up-5t55-10M770
Jan  8 15:46  jan07-cu26986-p60up-5t55-10M770  

corresponding to c. 3t60 ran on the C212. (That's 79K
curves with B1 = 400M, gmp-ecm default B2.) I also
had t60's on the C202 and C207, which are from the recent
base-3 extension, where Sam was saying that he ran t60's
before adding them to the regular list. I'd say that
these have already survived ECM testing. -Bruce

(Incidently, 7p373 C303 has also survived a t60 (with B1 = 600M),
and I'll run a bit further.)
3) Message boards : NFS Discussion : 3,637+ factors (Message 1032)
Posted 17 Oct 2012 by bdodson*
bdodson ,

BTW, aren't you going to go after first place here at NFS@Home? It would also be a way to quickly finish 2,1037- sieve until the end of the year.


I'm happy to see Greg in first place. The University discontinued
the semi-public linux labs that I was using for most of the nfs@Home
computing I was doing. Those were commodity quadcores. I ran some
on the replacement research machines, but nfs sieving was causing them
to need occasional rebooting, which meant asking sysadmin assistance
instead of heading over to a lab where I could hit reboot. I'm still
doing gnfs sieving on our research machines, just not on Boinc - they're
run under a PBS scheduler, and don't allow interactive logins.

-Bruce (11p301 tested to t60, working on 11m301)
4) Message boards : NFS Discussion : 3,637+ factors (Message 1023)
Posted 10 Oct 2012 by bdodson*
How much ecm was done on this integer?

Same thing I was wondering on seeing p63*p66. Looks
like 26,987 curves with

Using B1=400000000, B2=5821851770290, polynomial Dickson(30)

with GMP-ECM 6.3 (Dec 2011) and 6.4 (May, 2012). This
was supposed to be a test sufficient to find a p60 to
probability of 62%; the limits are non-trivially above
p60-optimal (B1=260M), but well below p65-optimal (B1=850M).

This was a 15e number? If I recall, I went to 2t60 on
the most recent 16e pretest, but even that wouldn't have
given very substantial odds at finding one of p63, p66.
Maybe 50-50, if I'd doubled my curve count.

Good you've asked though; how much do we have on 11p301
and 11m301? I've just finished .6t60 on the c210 and
.4t60 on the c261 as initial passes for this recent
extension to the Cunningham lists. Not sure whether Sam
got his "usual" t60 before adding the extension; as these
two most recent ones were added early (to catch the p79
record!). Perhaps it's worth adding some more?

-bdodson (not sure that my p70 will stay in the top5 for 2012!)
5) Message boards : NFS Discussion : p52 ecm factor of 7, 749L, complete (Message 905)
Posted 10 Jun 2012 by bdodson*
i am not understand this forum

The numbers being factored in this project are factored
using a sieving method; specifically by the "Number
Field Sieve" = NFS. This is a method intended to be
applied to "worst case" factorizations, a number with
only two or three prime factors, the smallest with at
least 55-digits, preferably at least 60-digits.

If you look under "Status of Numbers" you have to go
all the way back to Nov 17, 2010 to find a prime factor
below 60-digits (2,2086L factored as p55*p149; the
smallest prime factor having 55-digits). Until recently
almost all of the numbers being factored are taken from
the Cunningham project, with a few exceptions for numbers
of interest from other projects. These are not manufactured
numbers, like RSA-keys, designed to have just two large
prime factors. If one picks a random composite number
with between 155-digits to 310-digits (that's 512-bits to
1024-bits) very few will fail to have a prime factor
below 25-digits. For a number with smallest prime factor
between 25-digits and c. 60-digits the Number Field Sieve
is not the best method. That factorization from Nov 2010
was referred to as an "ecm miss" because the 55-digit prime
was not found by the best method. There are other boinc
projects devoted to using ecm to find these "mid-sized"
prime factors; again NFS is intended only for worst-case

This "forum", the thread "p52 ecm factor ...", is a report
of an ecm success. The number 7,749L was a candidate
selected by Greg as a possible number for NFS@Home to
factor with the number field sieve, but I was fortunate
to find the 52-digit prime during pretesting, before sieving

Hope this helps. -bdodson*

6) Message boards : Questions/Problems/Bugs : Some questions (Message 815)
Posted 25 Mar 2012 by bdodson*

...M1061 is "on hold". The current siever has run out
of special-q to use and he does not have enough relations.
...he hopes to put out the new siever during
spring break.

What is special-q and what is the spring break? I live in Singapore, so all this doesn't make sense to me.

Among the google hits from "special-q factoring" you may find links
to mersenneforum, as well as several technical reports on which
special-q have been used in various "number field" and SNFS ("special"
number field) factorizations. They are used in the "lattice sieving"
step in the "number field sieve".

This is a message board for a boinc project that uses special-q for
lattice sieving. There are many prerequisites necessary for even a
general description, which are outside of this project's focus on people
intending to request and complete sieving tasks.

You might try wikipedia for "spring break". -bdodson*

@Bob --- We discussed the selection of 5p433, and here's Greg's view

I'm hoping to start 5p433 in a few weeks now. ... M1007 might be more attractive scientifically,
but 5p433 adds variety and size.

M1007 was a candidate from the list of targets of the EPFL effort using
ECM on their PS3 cluster. We had just recently completed M1031, and
even then were hoping that M1061 would finish in the next few weeks.

The other numbers weren't in consideration on our list.
7) Message boards : Questions/Problems/Bugs : Some questions (Message 807)
Posted 18 Mar 2012 by bdodson*
Your previous post answers all my questions, except part of number 2.

(a record-setting number, and ... - the last one from George Woltman's list of 2,n- with n < 1200 having no known factor).

2^1061-1. What's the next Mersenne without known factors? ...

Until recently, this was M1237, but there was a spectacular ECM factor
with 70-digits found using a network of PS3's. The cofactor has
303-digits, and is composite, so it could be a very long time before
we know the rest of the factors. There's currently an effort on
mersenneforum to factor M929, after which M947 will be the smallest
not completely factored. Note that M1007 is currently fourth, in
about the same range as 2p1000, which is first on the 2+ list, and
10th on the Cunningham Most Wanted list.

So anyway, the GIMPS report currently lists M1277 as the next smallest
after M1061, then M1619. The exponent range there is up to 10000
looks more than 50 less than 100


Just for reference, ...

But you forgot 7,355+! What's the status of that?

I thought you knew that. So long as tasks for 2p1000 are being
distributed, that means that Greg doesn't need more reports to
start the matrix step. These 15e projects are smaller numbers,
and the matrix is most likely running on the cluster at Cal State

-bdodson* (still NFS@Home's number 1 contributor, hoping that both
Greg and I will get bumped by someone else!)
8) Message boards : Questions/Problems/Bugs : Some questions (Message 805)
Posted 16 Mar 2012 by bdodson*
I have some questions regarding this project:

1. I have received a workunit that begins "S5p433". I have received another workunit that begins "S2p1000b". I can understand the second one (it's for 2,1000+), but not the first - that seems to be 5,433+, but it's not on the Status of Numbers page. What's going on here? And what do the names of the workunits mean in the first place?

2. What's the status of the sieving for 2,1061- and 7,355+?

Parts of these two questions are related. The Cunningham number
5, 433+ is the project that is intended to follow 2, 1061-, once
2, 1061- is completed. If you're receiving tasks for 5p433, that's
a good indication that 2, 1061- has completed sieving, or will soon;
provided that the next step is up and running (the matrix step,
a non-bonic calculation, done under the terragrid grant, on a
national supercomputing site). In particular, 5p433 is the next
number that uses the 16e siever.

3. When are the numbers not yet started (ie. 7,365- / 10,305+ / 11,290+ / 2,1000+) going to start?

4. Is there a visual app (like those for WCG and Rosetta@home) that will display the progress of sieving for a workunit?

5. Are there any plans to factor more non-Cunningham numbers (like EM48)?

The other numbers listed on the status page are all 15e projects (that's why
5p433 is being added), and one expects that they'll be done in order,
2,1000+ first then the next, 11,290+, then ... I can't speak to plans
for visual apps or non-Cunningham numbers; I would expect that a fair
part of Greg's attention is going to the next step for 2,1061- (a record-
setting number; and the most wanted Mersenne number --- the last one
from George Woltman's list of 2, n- with n <1200 having no known factor).

9) Message boards : Questions/Problems/Bugs : 200 digits number from the book "In Code: A Mathematical Journey" (Message 725)
Posted 3 May 2011 by bdodson*
That book was written a decade ago, ... I cannot justify spending this much of the NFS@Home participants' and supercomputer time for a number that's just a curiosity. Sorry.

I'm not curious, even. For comparison, the largest GNFS currently on
NFS@Home's list is 183.7. I hear that adding five digits to the size
in GNFS in this range doubles the difficulty (runtime, in particular);
that's three doublings (at a minimun), 8-times as difficult.

Also, I wondered on reading the original post how closely the person
posting had looked at the two numbers referred to, RSA200 and then
RSA768 (at 232-digits, maybe 233?). Both numbers were done by a single
non-public group, with dedicated hardware; a group that includes the
people that wrote the original lasieve code, using completely different
linear algebra code, that I don't believe is yet in the public domain.
The current NFS@Home project on SNFS is the first pass at a public
approach to the records set by that group; Bonn (GNFS200), Bonn-NTT-EPFL
(SNFS1024) then Bonn-NTT-EPFL again (GNFS232) over a decade-or-more's work.
We're just now about to meet, and then break, their SNFS record --- check
the status page --- 2,1031- SNFS 310.7 and 2,1061- SNFS 319.7, respectively.

For a comparable public project on GNFS, mersenneforum may have the best
chance; having recently completed GNFS187, and just starting on GNFS197.
The first attempt at the GNFS matrix failed, after months of computing;
and we were very happy that the second attempt succeeded. A suggestion
that GNFS200 is now on the borderline of being routine, as a public project,
just isn't correct. Finding and multiplying two 100-digit primes is indeed
a plausible project for a computing beginner; hardly even requiring a
math coding prodigy. Breaking 200-digit composites isn't yet in that range.

-bdodson (still NFS@Home's top contributor; first past 50M credits)
10) Message boards : Questions/Problems/Bugs : All work error out? (Message 713)
Posted 24 Mar 2011 by bdodson*
I shifted my host to the smaller lasievee (v1.08)till this is sorted out.
Hmmmm......no luck;
24-3-2011 1:09:23 NFS@Home Message from server: No work is available for 15e Lattice Sieve

Yes. The 16e tasks all errored out in under 10 seconds; many
people had settings to take other tasks if there weren't any 16e's
left (that's 16e = lasievef); so the 15e tasks are all done also.

We need Greg's attention on this one. -Bruce
11) Message boards : NFS Discussion : AndrOINC (Message 691)
Posted 27 Jan 2011 by bdodson*
Are you sure that even with your alghorithm, thousands of computers and GPU support it will still take ages? I thought that sieve is a really fast method so we can crack RSA 1024 with huge power(~4000 computrs working on it) within few years..

In a gnfs factoring project, the result of the sieving effort
is a sparse matrix problem, that has to be solved to break the
key. Computations on the matrix problem (even in the distributed
version used to break RSA768) are parallel, with heavy data transfer
between compute nodes --- that is to say, an expensive supercomputer
calculation. NFS@Home is currently working on 1024-bit SNFS, while
RSA keys require GNFS. There has recently been a five-or-more year
gap between the SNFS record and the corresponding GNFS record for
the same number of bits. So SNFS768 was set in 2000, RSA768 in
Dec 2009; SNFS512 in 1993, RSA512 in 1999. For 1024-bits, SNFS1024
was first broken in 2007, but not by a public project.

Switching from bits to digits, 768-bits is 233-decimal and 1024-bits
is 310-decimal (resp. 512-bits, 155-decimal). NFS@Home has been working
up towards the 310-digit _public_ SNFS record, and most recently broke
295-digits (Nov 29, 2010). The matrix for 300-digits is currently running
under a terragrid grant --- for example, previous sparse matrices from
NFS@Home were run on the first of these two clusters


The software being used has not been tested in this range --- we're
the first. And that's 295-digit, 300-digit and then 310-digit, for
public SNFS. And then another 5-10 years from SNFS to GNFS, on a
computer that hasn't been built yet.

Hope this clarifies matters. -bdodson*
12) Message boards : Questions/Problems/Bugs : 4 sieving and 2 not yet started. What's next??? (Message 683)
Posted 14 Jan 2011 by bdodson*
Why 2,979+ instead of 2,947+? Why not do the holes in order?

We're currently doing 1040+ and 1099+ by gnfs (15e), and
997+ and 1031- by snfs (16e), and you're still unhappy that
the numbers from 2+ and 2- aren't being done in order?

Also, I wonder whether you object to the Wagstaff-Selfridge
lists of Wanted and Most Wanted numbers? They're not just
taken in order, with 1061- as a recent addition. Will you
object if Greg follows 1031- with 1061-, instead of taking
the 2- list in order?

I'm fairly certain that you won't mind!, Regards, Bruce*
13) Message boards : NFS Discussion : p52 ecm factor of 7, 749L, complete (Message 681)
Posted 14 Jan 2011 by bdodson*
And the cunningham book leaves me confused as to exactly what 7,749L means...can you explain briefly?


I had to look this one up. Mersenneforum reports

Originally Posted by LUCAS
(7^{14k-7}+1) = (7^{2k-1}+1)

One of those factors is 7L, the other 7M. The first post by
Raman in the thread "Aurifeuillian Factorizations" under the
subforum "Cunningham Tables" (it's not a sticky thread; you
need to scroll down a page or three). Uhm, sub-subforum, under
"Factoring Projects". (And 14k-7 = 749, so 14k = 742 and k = 73.)

Greg would have picked these seven numbers up from "Appendix C"
on the main Cunningham page, which lists composite cofactors
after removing all known factors. The "Main Tables" lists the
known factors and then C238 in the 7+ table, under 749; where
C238 is the number I factored, given in appc1210 (the latest
update to Appendix C).

The other six numbers are ready to be sieved (as 15e projects),
with ECM having failed to find any other factors after an effort
sufficient to find/remove 55-digit prime factors. If you scroll
through the factorizations found by NFS@Home on the "Status of Numbers"
link, you'll see one 54-digit prime, and one 55-digit prime. Those
were ECM misses; reflecting the fact that ECM is a probabilistic method.
The next smallest prime found looks to be a 58-digit prime, perhaps
a borderline case. I don't claim to be able to reliably find/remove
primes at/above 60-digits (to 62%, or to 80%, respectively). I do
make a larger effort on numbers for the large memory 16e projects;
perhaps sufficient to find 57-digit primes. The current 16e project
was subjected to an intensive ECM effort on a network of PS3's, which
we believe was sufficient to find a 65-digit prime factor (an average
65-digit prime, to 62% chance, so 2-out-of-3).


14) Message boards : NFS Discussion : p52 ecm factor of 7, 749L, complete (Message 680)
Posted 13 Jan 2011 by bdodson*
somewhat dumb questions here:
We have some factors...how do we *prove* that those factors are themselves prime rather than simply probably prime?

And the cunningham book leaves me confused as to exactly what 7,749L means...can you explain briefly?


Primality proofs are "easy", certainly through 1000-decimal digits;
the record (for a random probable prime) is 20,000-digits. Check out
any text on computational number theory; or Pomerance-Crandal for
the cannonical math reference.

Here's wiki:
A primality test is an algorithm for determining whether an input number is 
prime. Amongst other fields of mathematics, it is used for cryptography. Unlike 
integer factorization, primality tests do not generally give prime factors, 
only stating whether the input number is prime or not. As of 2010[update], 
factorization is a computationally hard problem, whereas primality testing is 
comparatively easy (its running time is polynomial in the size of the input). 
Some primality tests prove that a number is prime, ... 

and, under "Fast Deterministic tests":
Near the beginning of the 20th century, it was shown...The first deterministic
 primality test significantly faster than the naïve methods was the cyclotomy 
test; its runtime can be proven to be O((log n)clog log log n), where n is the
number to test for primality and c is a constant independent of n. Many further 
improvements were made, but none could be proven to have polynomial running time. 
The elliptic curve primality test can be proven to run in O((log n)6), but only 
if some still unproven (but widely assumed to be true) statements of analytic 
number theory are used[which?]. Similarly, ...

In 2002 the first provably polynomial time test for primality was invented by 
Manindra Agrawal, Neeraj Kayal and Nitin Saxena. The AKS primality test, runs 
in Õ((log n)12) (improved to Õ((log n)7.5) in the published revision of their 
paper), which can be further reduced to Õ((log n)6) if the Sophie Germain 
conjecture is true.[3] Subsequently, Lenstra and Pomerance presented a version 
of the test which runs in time Õ((log n)6) unconditionally.[4]  

AKS is slow in practice; ECPP is the method of choice for a random number.

If you're looking for more online info, there's Chris Caldwell's prime pages,
which has 211 references:

15) Message boards : NFS Discussion : p52 ecm factor of 7, 749L, complete (Message 671)
Posted 26 Dec 2010 by bdodson*
Here's a number that's not going to get to the Status
page, previously not having gotten much attention as
composite with 238-digits, 7,749L factors as

Found probable prime factor of 52 digits: 2318868300888214432629820239511448448889333514213573
Probable prime cofactor 1939504822579547933451707578025151213557965141384883143005746538912073577908143479868235664035548012336930
639254767137411729071632032786487463263511862021608860213750543945070313863284691 has 187 digits

An ecm success; one fewer number to sieve. Not to
worry, Greg has another six candidates, presently in
ecm pre-testing.

-bdodson* (newest member of team Sicituradastra)
16) Message boards : Questions/Problems/Bugs : Error's while Computing ? (Message 656)
Posted 18 Dec 2010 by bdodson*
unlike Paladin/.Steve with his #1 _world_
bonic ranking, who likely doesn't need any extra distractions

What is it Bruce, the #1 Ranking or just me that you don't like, I've never done anything to this Project but run some Wu's.

Whoa!! The number 1 Ranking is a fantastic acomplishment; I'm
a huge fan. Of the boinc contributors with what appears to be
nearly unlimitted resources (top 100, say), you're one of our
most interesting contributors. You were one of the first boinc
contributors to contact me, and I spend quite a bit of time trying
to learn from what you do. You can be somewhat abrasive, but that's
not necessarily a bad thing; among friends. I'm 110% certain that
I don't dislike you. Puzzled sometimes, perhaps; but in a good

But I get the feeling you think I've harmed the Project in some way. Just because I'm not attached to the Project 100% like you doesn't mean I don't like the project, it's just that there are 100 other Projects out there to run besides this one.

I have to buy all my own equipment & pay for all my own electricity on a Retirees Pension unlike you who can use the "our large Linux workstations" from the University I take it free of charge. So if I choose to run other Projects then that should be my choice and without fear of animosity from some Project that feels I should devote all my time and resources to it instead of spreading the Pharm out some to benefit more than 1 Project ... Still your Friend, .Steve/Paladin/PoorBoy

One of the things I've learned is the extent to which projects that
have apps the make good use of GPUs have an advantage in attracting
contributors. I'm guessing, but I wonder whether 95% (or more) of
your credit is from GPU contributions? I was just reading that you
favor 580's. I'm stunned to hear that you purchase all of the Pharm
with your own funds. That's some Retiree Pension, we all should have
been so lucky; I'm just about to turn 61, but it looks like I'll need
an extra 5-7 years after my age 66 to make-up for our 401k's having
become 201k's. And besides, I'm fairly sure that you've been very
well informed in deciding how to spend the funds you have available.

Uhm, you couldn't choose to direct your GPU resources here; since
we don't know how to do number-field-sieving (nfs as in snfs/gnfs,
used in the lasieve's) with GPUs. I've been trying to convince anyone
I can that finding polynomials is a really good thing; but I'm not
sure that I've succeeded at convincing myself --- doesn't appear to
be a couple of orders of magnitude of a bump, the way a really killer
GPU app should be. So we're discussing the remaining 05% of your
resources; and they're for sure yours to allocate as you choose.
And, uhmmm, "fear of animosity"? Hmm; I hope not.

So, anyway, after a year-or-so of watching your GPU acomplishments,
I did in fact convince our HPC committee to purchase two Nvidia cards
(actually, that's not my fault; the engineering faculty wanted
double prec. floating point, so what we got was the tessla 20s).
They seemed fairly happy about the $9K purchase; a large blurb
on the main web page. I'm happy to be able to report that I've
just today managed to get primegrid's Proth Prime sieve to run;
and it's already running credit circles around my NFS@Home credit;
looks like 100K credit from a rather large pool of x86_64's by CPU;
vs 500K credit from just the two cards -- looks like they're just
a tad slower than the 580's. So even I won't be 100% NFS, with just
a week of two of Proth sieving.

You carry a lot of weight. By right of having earned it. I'll only
be one of 100's if I manage to break into the top 1000. So what can
I do to make amends for having left the wrong impression in my posts?
Would switching teams help? I'm not getting much, if anything, from
BonicStats. With warmest regards, your Friend, Bruce/bdodson.
17) Message boards : Questions/Problems/Bugs : Error's while Computing ? (Message 653)
Posted 14 Dec 2010 by bdodson*
You're right. This number does have an unusually high failure rate of about 10% on Windows but not on Linux, and it's not the usual memory error. ...it will be a few weeks before I can get to it. Thanks for letting me know!

Hi Greg and hello everyone.

I thought I would also report in.

in case my computer (a Dell Precision Work Station) has information you need in your investigations of these computational errors.

I'm also getting a lot of Computational errors.

I'm not an educated person, but I love Mathematics and numbers, and so I want contribute some spare CPU cycles from my computer to your Project. NFS@Home

I Wish you much success with your project NFS@Home
Best Wishes

Thanks for the report (if Greg will pardon my presumption) and
the wishes. I wasn't able to tell whether the computing errors
were bothering you (unlike Paladin/.Steve with his #1 _world_
bonic ranking, who likely doesn't need any extra distractions).

I do run lasievef/16e tasks on our large linux workstations; but
have the five with lower memory (1Gb/core) working on the smaller
lasievee/15e tasks (a total of 20 xeon cores). As I sometimes teach
an intro course on (mathematical) cryptography, and have been
contributing to applied cryptographic computing since 1995 (starting
with the first RSA120); I have more than enough education, much of
it since my pure math phd (1976).

I'm not entirely sure that I can make a case for snfs projects under 15e,
as compared to snfs projects under 16e. But we have two serious gnfs
projects next in the 15e queue (found in the "Status of Numbers" link,
on the main NFS@Home page). First, the math part of a gnfs project is
substantially more elaborate than what is required for snfs ("512-bits in
1993" for snfs -vs- "512-bits in 1999" for gnfs; and then, "768-bits in
2000" for snfs -vs "768-bits in 2010" for gnfs!). Next, the current computing
issues are very interesting. In particular, the project definition for these
two 180-digit gnfs numbers was found (by Greg) using GPU computing on
nvidia/tessla graphics cards. You won't see a difference in the WUs
(unless you locate the "gnfs polynomial" used in the project definition),
but these results will be at least as interesting as the current 16e snfs.

Regards, bdodson

(No promises about the _next_ 16e snfs, and the one after that, which are
the reason for Greg's push to larger/harder projects; but those may be even
worse for low memory computing.)
18) Message boards : Questions/Problems/Bugs : Error's while Computing ? (Message 634)
Posted 9 Nov 2010 by bdodson*
If your running Linux the 2 Lines that read in the App File >>> primegrid_ppsieve_1.30_windows_intelx86__cuda23.exe <<< must read as the Linux executable that your using ...

That was exciting. I switched these two lines to match the
linux binary I downloaded


and that ran through several 10's of "computation errors".
My primegrid account gives the error message

process exited with code 22 (0x16, -234)
execv: No such file or directory


Likewise, the boinc Manager message says (repeatedly)

starting pps_sr2sieve_...
starting task pps_... using pps_sr2sieve version 130
computation for task ... finished
output file pps...0_0 for task pps...0 absent

I suppose, sooner-or-later, someone should object to this off-topic
exchange; even between 2 of the present top3 on NFS@Home, but
I wonder that we're still making progress?

Looks like the error message just reports that the expected
output file is missing? -Bruce

19) Message boards : Questions/Problems/Bugs : Error's while Computing ? (Message 632)
Posted 9 Nov 2010 by bdodson*
Are you running Linux ?

Yes. Although I was noticing that the Berkely site lists instructions
("yum ...") I don't understand for fedora7; while we use a ("close") variant
"centos" (as do many university sites with heavy computational interests).
The linux versions 56, 58 don't seem to run nearly as well as 6.10 used to;
and I was hoping to get a recent version more likely to be GPU aware.

... if not you need the Windows .exc, best you bring it up in the PG Forum in the Sieving Forum. There's guys there that know a whole lot more than me when it comes to setting up GPU's for running the Sieve Wu's. I had to be walked thru it myself to get a few of mine running the GTX 4xx Cards ...

PS: Just started today to try and get my ATI's to run the Wu's, supposedly it can be done as a few have already done it but I'm just getting started on it now so will see how it goes ...

Now that would catch some eyeballs. The people looking at this are
computing types; while this boinc NFS project adapted an initial
version set up by hackers for breaking RSA-keys on calculators (TI...).

I'd probably best get the fermi cards back to gnfs polynomials. The
current 15e project, G2p1195, uses a polynomial Greg found using their
tessla cards. We've been working with the people that wrote the GPU
code; and appear to have gotten a marginal improvement on the polynomial
for the next project, 5M895.

20) Message boards : NFS Discussion : 3,607- factors (Message 631)
Posted 9 Nov 2010 by bdodson*
Is this number be factored use degree 6, ...

but I read a article which suggest using degree 7 for SNFS 280 to 350.
So what's the matter here?

I'm somewhat curious as to which article you were reading; you're
most likely careful about sources, but the phrase "I read it on the
internet" (which you didn't use, I know) is often followed by info
that's not very reliable.

Another possible issue is that the 16e siever we're currently using
has some improvements (and/or corrections) in the assembly code due
to our friend Batalov. The initial source code of Franke/Kleinjung
is not very portable, and notoriously intricate, so that even a usually
reliable author may not have had the best code to work with. Establishing
a well docummented public source of data is one of the points of this
boinc project. There are very few public SNFS factorizations above
difficulty 280; and the author is quite likely making use of relatively
limited simulations, rather than examining the "entire sieving range yield".


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