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pepi37 2015-07-11 20:51

Can you post me sieve with removed composite?
Thanks

Batalov 2015-07-11 21:42

1 Attachment(s)
Sure.

pepi37 2015-07-11 21:52

Something is very fishy with this sieve

Original sieve contains 5600 candidates, when you removed composite it has 4551 candidates.

But when I make test sieve got this

Read [COLOR=Magenta]7027[/COLOR] terms for 4*155^n+1 from NewPGen file `155.txt'.
Split 1 base 155 sequence into 45 base 155^120 subsequences.
Recognised Generalised Fermat sequence A^2+1
Using 4 Kb for the baby-steps giant-steps hashtable, maximum density 0.15.
Baby step method gen/4, giant step method new/4.
Using 128Kb for the Sieve of Eratosthenes bitmap.
Expecting to find factors for about [COLOR=Magenta]1138.47 terms.[/COLOR]
sr1sieve 1.4.5 started: 750036 <= n <= 999992, 110000000000 <= p <= 15000000000000
110173104133 | 4*155^905128+1
110259397681 | 4*155^967174+1
p=110259523441, 29853266 p/sec, 2 factors, 0.0% done, 1 sec/factor, ETA 17 Jul 23:09
sr1sieve 1.4.5 stopped: at p=110278915793 because SIGINT was received.
Found factors for 2 terms in 9.368 sec. (expected about 0.70)

7027 - 1138 ( to be at 15000000000000 as original sieve) = 5889
Can expected number of candidates be so different ? 5889 compared to 5600 (289)

Batalov 2015-07-11 22:11

[QUOTE=pepi37;405685]Something is very fishy with this sieve

Original sieve contains 5600 candidates, when you removed composite it has 4551 candidates.

But when I make test sieve got this

Read [COLOR=Magenta]7027[/COLOR] terms for 4*155^n+1 from NewPGen file `155.txt'.
Split 1 base 155 sequence into 45 base 155^120 subsequences.
Recognised Generalised Fermat sequence A^2+1
Using 4 Kb for the baby-steps giant-steps hashtable, maximum density 0.15.
Baby step method gen/4, giant step method new/4.
Using 128Kb for the Sieve of Eratosthenes bitmap.
Expecting to find factors for about [COLOR=Magenta]1138.47 terms.[/COLOR]
sr1sieve 1.4.5 started: 750036 <= n <= 999992, 110000000000 <= p <= 15000000000000
110173104133 | 4*155^905128+1
110259397681 | 4*155^967174+1
p=110259523441, 29853266 p/sec, 2 factors, 0.0% done, 1 sec/factor, ETA 17 Jul 23:09
sr1sieve 1.4.5 stopped: at p=110278915793 because SIGINT was received.
Found factors for 2 terms in 9.368 sec. (expected about 0.70)

7027 - 1138 ( to be at 15000000000000 as original sieve) = 5889
Can expected number of candidates be so different ? 5889 compared to 5600 (289)[/QUOTE]
file `155.txt' is your own file, so if anything is fishy it could be with that file.
[QUOTE=pepi37;405685]Can [U]expected[/U] number of candidates be so different ? 5889 compared to 5600 (289)[/QUOTE]
Of course it can. That's why the word "[U]expected[/U]" is used. The "[U]expected[/U]" number of candidates can be way off epecially because the estimate is for a irreducible form, while this form is algebraically reducible for a fraction of candidates.

I like that srsieve [B]does [/B]recognize the GFN form and [B]can [/B]as a result sieve faster (this is based on the fact that only primes of form 4k+1 can divide a A^2+1 form). On the other hand, srsieve does [B]not [/B]recognize Aurifeillian fraction and does not remove it - but as the closing line from 'Some Like It Hot' goes, "No one is perfect".

pepi37 2015-07-11 22:13

Thanks Batalov, so lets LLR-ing start :)
And thanks for reduce LLR time for about 60 days!

rogue 2015-07-11 22:23

[QUOTE=Batalov;405687]I like that srsieve [B]does [/B]recognize the GFN form and [B]can [/B]as a result sieve faster (this is based on the fact that only primes of form 4k+1 can divide a A^2+1 form). On the other hand, srsieve does [B]not [/B]recognize Aurifeillian fraction and does not remove it - but as the closing line from 'Some Like It Hot' goes, "No one is perfect".[/QUOTE]

If you have a code change that I can apply to srsieve...

Batalov 2015-07-12 16:07

[QUOTE=pepi37;405688]Thanks Batalov, so lets LLR-ing start :)
And thanks for reduce LLR time for about 60 days![/QUOTE]
I ran sr1sieve for a bit to check the estimates and removed two more candidates for you:
[CODE]15189078811981 | 4*155^968110+1
[STRIKE]15239240636801 | 4*155^943524+1[/STRIKE] (already removed, because it is 4*A^4+1)
15316822815461 | 4*155^761998+1
[/CODE]

Batalov 2015-07-12 16:32

[QUOTE=rogue;405691]If you have a code change that I can apply to srsieve...[/QUOTE]
As my granddad used to say, "Це діло треба розжувати." (Got to ruminate on this one.)
Could we make some small steps?

The 4*A^4+1 recognition can be added precisely where "Recognised Generalised Fermat sequence A^2+1" is emited. Right?
At this point all n divisible by 4 should be eliminated.
This goes for other k :: (k/4) = m^4; that is, k=4, 64, ...2500...

One other simple case is when b=m^2, and k :: (k/4) = m^4; here, all even n should be eliminated. This was the case for S100 (k=64).

But to do is right, we also need to recognize cases where small factors of b can "leak" from the base power. For that, the isPower script is the prototype for many patterns. I don't remember where it was posted, so I attached a copy of it here:
[CODE]#!/usr/bin/perl -w

use Math::BigInt;

line: while(<>) { # this is a pl_remain.txt file; it has k*b^n+c lines only
next unless /^\s*(\d+)\*(\d+)\^(n|\d+)([+-])1/ && $1 && $2;
$k = Math::BigInt->new($1);
$a = Math::BigInt->new($2);
my @powers = ($4 eq '+') ? qw(3 5 7 11) : qw(2 3 5 7 11);

if($4 eq '+') {
print "Mod 0|4 Aur\t$_"
if($k==4 || $k==64 || $k==324 || $k==1024 || $k==2500 || $k==5184);
# $b = $k->copy()->bmul($a);
# print "1|4 Aur\t$_"
# if($b==4 || $b==64 || $b==324 || $b==1024 || $b==2500 || $b==5184);
# $b->bmul($a);
# print "2|4 Aur\t$_"
# if($b==4 || $b==64 || $b==324 || $b==1024 || $b==2500 || $b==5184);
# $b->bmul($a);
# print "3|4 Aur\t$_"
# if($b==4 || $b==64 || $b==324 || $b==1024 || $b==2500 || $b==5184);
}
foreach $m (@powers) {
$b = $k->copy()->broot($m);
if ($b->copy()->bpow($m) == $k) {
if ($a->copy()->broot($m)->bpow($m) == $a) {
print "* x^$m\t$_";
next line;
}
print "Mod 0($m) $b^$m\t$_";
}
}
for ($n=1; $n<$powers[$#powers]; $n++) {
$k->bmul($a);
foreach $m (@powers) {
next if $n>=$m;
$b = $k->copy()->broot($m);
print "Mod $n($m) $b^$m\t$_" if ($b->copy()->bpow($m) == $k);
}
}
}
[/CODE]
I don't know how easy it would be to implement the same rules in sr*sieve.

pepi37 2015-07-12 16:50

[QUOTE=Batalov;405722]I ran sr1sieve for a bit to check the estimates and removed two more candidates for you:
[CODE]15189078811981 | 4*155^968110+1
[STRIKE]15239240636801 | 4*155^943524+1[/STRIKE] (already removed, because it is 4*A^4+1)
15316822815461 | 4*155^761998+1
[/CODE][/QUOTE]

Thanks 2.5 hours less :)
What is removal rate if I may ask?

Batalov 2015-07-12 16:59

[QUOTE=pepi37;405725]Thanks [B]2.5 hours less[/B] :)
What is removal rate if I may ask?[/QUOTE]
It is slow, about the same as LLR. I'd say this sieve depth is just right.

I sieved on 4 cores, 0.1P interval each (that's from 15.0P to 15.4P); each took ~1.1 hour. And as you can see, 2 factors were removed (we don't count the third, because you can assume that it is [B]not [/B]in the sieve, already; I simply left n divisible by 4 in the input file).
That's 1 factor / [B]2.2 hours[/B]. So just proceed with LLR.

pepi37 2015-07-12 17:04

[QUOTE=Batalov;405726]It is slow, about the same as LLR. I'd say this sieve depth is just right.

I sieved on 4 cores, 0.1P interval each (that's from 15.0P to 15.4P); each took ~1.1 hour. And as you can see, 2 factors were removed (we don't count the third, because you can assume that it is [B]not [/B]in the sieve, already; I simply left n divisible by 4 in the input file).
That's 1 factor / [B]2.2 hours[/B]. So just proceed with LLR.[/QUOTE]

Yes, 34 candidates is already done :)
Small step for humankind, huge step for me :)


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