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Search: Posts Made By: danaj
Forum: Factoring 2020-06-10, 04:30
Replies: 13
Views: 541
Posted By danaj
https://en.wikipedia.org/wiki/Modulo_operation ...

https://en.wikipedia.org/wiki/Modulo_operation

For even more interesting reading. It's implementation defined in C (this bit me a few times while doing printer firmware, because our HP/UX...
Forum: Computer Science & Computational Number Theory 2020-05-24, 12:35
Replies: 26
Views: 7,733
Posted By danaj
:smile: :smile: :smile: :smile:

:smile: :smile: :smile: :smile:
Forum: Prime Gap Searches 2019-05-03, 11:28
Replies: 21
Views: 1,169
Posted By danaj
I ran to 10^20 last night without finding any. I...

I ran to 10^20 last night without finding any. I just spent a few minutes and tested the other three types to 10^17 without finding any.

I did a simple look at the 3rd type of 11 twins to 10^19...
Forum: Prime Gap Searches 2019-05-01, 16:31
Replies: 21
Views: 1,169
Posted By danaj
$ perl -Mntheory=:all -E...

$ perl -Mntheory=:all -E 'prime_set_config(verbose=>2); say for sieve_prime_cluster(0,1e14,2,6,8,18,20,30,32,36,38,48,50,60,62,78,80);'
cluster sieve found 1 residues mod 30
cluster sieve found 1...
Forum: Prime Gap Searches 2019-05-01, 16:28
Replies: 21
Views: 1,169
Posted By danaj
For your second example, it takes 40 seconds to...

For your second example, it takes 40 seconds to test to 10^14 using sieve_prime_cluster in serial on my macbook. Use the ktuplet-threads.pl example script to run in parallel.

29
2595051759329...
Forum: Programming 2019-04-24, 13:07
Replies: 7
Views: 4,049
Posted By danaj
It is about time. I know WraithX submitted his...

It is about time. I know WraithX submitted his code to them years ago. IIRC it is a slower than mine, though in a nice neat library. I'd like to see either a standard Selfridge strong Lucas test,...
Forum: Factoring 2019-04-03, 15:28
Replies: 55
Views: 2,731
Posted By danaj
I also got from the paper that SM was not the end...

I also got from the paper that SM was not the end goal, and I wasn't commenting on that. I think RM is certainly interesting and non-obvious.

Mainly since we've had discussions on this forum of...
Forum: Factoring 2019-04-02, 21:13
Replies: 55
Views: 2,731
Posted By danaj
The SM method looks to be Hart's OLF (as alluded...

The SM method looks to be Hart's OLF (as alluded to in the text) using a multiplier. Translating the "Simple Multiplication algorithm" from pseudocode into C becomes exactly my existing code for...
Forum: Forum Feedback 2019-03-27, 17:35
Replies: 17
Views: 1,524
Posted By danaj
Forum: Miscellaneous Math 2019-03-21, 16:36
Replies: 5
Views: 194
Posted By danaj
Good point. The sources don't even include a...

Good point. The sources don't even include a range for a in the theorems so they side-step it that way. Only when one has to actually go implement something to *find* a suitable value does this...
Forum: Puzzles 2019-03-21, 16:33
Replies: 213
Views: 26,904
Posted By danaj
Using GMP, assuming it all fits in memory and GMP...

Using GMP, assuming it all fits in memory and GMP scales fine, it's only 1.8 billion years to finish BPSW.

My single threaded Primo calculation came out to only exp( 4.01 *...
Forum: Miscellaneous Math 2019-03-21, 16:12
Replies: 5
Views: 194
Posted By danaj
Page 173-174 of Crandall and Pomerance discusses...

Page 173-174 of Crandall and Pomerance discusses this particular test. The theorem itself has no restrictions on a. Their remark is that one chooses random 1 <= a <= n-1. I'm not sure why one...
Forum: Miscellaneous Math 2019-03-10, 03:39
Replies: 5
Views: 237
Posted By danaj
For the case of base 2, you can go even one step...

For the case of base 2, you can go even one step further. It is even more discriminating than the Fermat and Euler tests, though less than a full strong pseudoprime (i.e. Miller-Rabin) test. To my...
Forum: Twin Prime Search 2019-03-09, 14:40
Replies: 8
Views: 1,765
Posted By danaj
Sigh, I now realize this was a test for the OP to...

Sigh, I now realize this was a test for the OP to show how well his method works. Well, ok um you can use the rest of this as a comparison I guess.




10^1000 + 9705091 is the smaller of the...
Forum: Prime Gap Searches 2019-03-09, 01:16
Replies: 23
Views: 1,318
Posted By danaj
Also see A055381 (https://oeis.org/A055381) and...

Also see A055381 (https://oeis.org/A055381) and A055382 (https://oeis.org/A055382). It seems they've already found the first ones up to 12-interprime.

Apparently there was a distributed project...
Forum: Prime Gap Searches 2019-03-08, 22:13
Replies: 23
Views: 1,318
Posted By danaj
Some simple transforms of Robert's code give a...

Some simple transforms of Robert's code give a ~2x speedup, or about 22e9/hour on a single-thread Macbook.

But then perhaps we notice that oneminus and oneplus are just the last and current prime...
Forum: Lounge 2019-03-04, 04:58
Replies: 108
Views: 7,370
Posted By danaj
It's interesting that a common list of long place...

It's interesting that a common list of long place (https://www.worldatlas.com/articles/the-10-longest-place-names-in-the-world.html) names claims...
Forum: Software 2019-03-02, 05:39
Replies: 19
Views: 1,364
Posted By danaj
Mathematica is a nice general purpose program. ...

Mathematica is a nice general purpose program. But it really isn't the fastest at a lot of things. Good GMP code or specific programs for operations can often be quite a bit faster. As others have...
Forum: Prime Gap Searches 2019-02-27, 21:54
Replies: 42
Views: 4,868
Posted By danaj
+20 points! If only the modern-day...

+20 points!

If only the modern-day Inquisition would stop changing the thread titles.
Forum: Other Mathematical Topics 2019-02-19, 17:13
Replies: 24
Views: 1,981
Posted By danaj
Dudley's paper "Formulas for Primes...

Dudley's paper "Formulas for Primes (https://www.maa.org/programs/faculty-and-departments/classroom-capsules-and-notes/formulas-for-primes)" (1983) contains some little formulas that produce either...
Forum: Prime Gap Searches 2019-02-15, 20:55
Replies: 23
Views: 2,125
Posted By danaj
Yes, quite a bit faster, albeit I don't know...

Yes, quite a bit faster, albeit I don't know anything as simple as modern primality testing. It still has a terrible growth rate so gets quite slow if you're spoiled by how fast we can do primality...
Forum: Factoring 2019-02-13, 21:38
Replies: 65
Views: 2,870
Posted By danaj
I'd recommend How to get started with factoring...

I'd recommend How to get started with factoring (https://www.mersenneforum.org/showthread.php?t=23078) on this forum. Lots of questions answered, lots of links.
Forum: Soap Box 2019-02-09, 04:33
Replies: 24
Views: 777
Posted By danaj
Oh, what sad times are these when passing...

Oh, what sad times are these when passing ruffians can 'nee'
at will to old ladies. There is a pestilence upon this land, nothing is
sacred.
Forum: Programming 2019-01-26, 20:46
Replies: 13
Views: 1,283
Posted By danaj
Paul, Could you send or point me to your...

Paul,

Could you send or point me to your test programs? I'd like to run on my machine to compare identical programs.

I was debating the merits of doing a comparison graph at different sizes,...
Forum: enzocreti 2019-01-26, 04:50
Replies: 9
Views: 290
Posted By danaj
It is quite possible. Run inside: time for...

It is quite possible.

Run inside: time for i in `seq 1 100`; do XXX; done for these XXX:

3.252s ./pfgw64s -k -Cquiet -f0 -u0 -q'...'
2.675s ./prp2 t.txt
1.917s perl -le 'use ntheory...
Showing results 1 to 25 of 902

 
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