mersenneforum.org  

Go Back   mersenneforum.org > Great Internet Mersenne Prime Search > Software

Reply
 
Thread Tools
Old 2020-06-22, 19:36   #397
rogue
 
rogue's Avatar
 
"Mark"
Apr 2003
Between here and the

2×11×269 Posts
Default

Quote:
Originally Posted by rebirther View Post
base S652 was running on all cores with -W16 but S913 did not (Ryzen 3950X) -->latest 2.0.3
Did you do both of these on the same machine?

For S913, it needs to reach a certain sieving depth before switching to multiple cores. I wonder if didn't get to that sieving depth or if it thought it needed to sieve deeper for S913 than S652 before switching. Can you post the pl_remain.txt files for both bases?
rogue is offline   Reply With Quote
Old 2020-06-23, 20:29   #398
rebirther
 
rebirther's Avatar
 
Sep 2011
Germany

23×107 Posts
Default

Quote:
Originally Posted by rogue View Post
Did you do both of these on the same machine?

For S913, it needs to reach a certain sieving depth before switching to multiple cores. I wonder if didn't get to that sieving depth or if it thought it needed to sieve deeper for S913 than S652 before switching. Can you post the pl_remain.txt files for both bases?

yes, both files attached
Attached Files
File Type: txt pl_remainS652.txt (645.9 KB, 12 views)
File Type: txt pl_remainS913.txt (513.2 KB, 12 views)
rebirther is offline   Reply With Quote
Old 2020-06-23, 21:29   #399
KEP
Quasi Admin Thing
 
KEP's Avatar
 
May 2005

13·71 Posts
Default

Quote:
Originally Posted by rebirther View Post
yes, both files attached
If my memory serves me right, when playing around with srsieve2, for curiosity only, I had to make a value of -w 10000000 (1e7), before srsieve2 used all 4 cores when sieving SR3 (for thousands of k's and very low p value). It also appeared, testing with sr383 sieve file, that for utilisation of ALL cores, one has to use a higher -w value than what is set as default - at least if one want's to use full ressources of ones machine.

Last fiddled with by KEP on 2020-06-23 at 21:29
KEP is offline   Reply With Quote
Old 2020-06-24, 13:48   #400
rogue
 
rogue's Avatar
 
"Mark"
Apr 2003
Between here and the

2·11·269 Posts
Default

Quote:
Originally Posted by rebirther View Post
base S652 was running on all cores with -W16 but S913 did not (Ryzen 3950X) -->latest 2.0.3
I found the cause. I'll try to get it fixed later today. The main issue is that it will slow down sieving for p > base. To work-around stop when sieving reaches p > base, then restart from the file of remaining terms.
rogue is offline   Reply With Quote
Old 2020-06-24, 19:12   #401
henryzz
Just call me Henry
 
henryzz's Avatar
 
"David"
Sep 2007
Cambridge (GMT/BST)

2×2,861 Posts
Default

Quote:
Originally Posted by rogue View Post
I found the cause. I'll try to get it fixed later today. The main issue is that it will slow down sieving for p > base. To work-around stop when sieving reaches p > base, then restart from the file of remaining terms.
Surely if it affects speed then mtsieve should detect when p becomes > base.
henryzz is offline   Reply With Quote
Old 2020-06-24, 19:34   #402
rogue
 
rogue's Avatar
 
"Mark"
Apr 2003
Between here and the

591810 Posts
Default

Quote:
Originally Posted by henryzz View Post
Surely if it affects speed then mtsieve should detect when p becomes > base.
Correct, but the code to detect that condition (when starting a new base) had a bug.
rogue is offline   Reply With Quote
Old 2020-06-24, 21:20   #403
henryzz
Just call me Henry
 
henryzz's Avatar
 
"David"
Sep 2007
Cambridge (GMT/BST)

2·2,861 Posts
Default

Quote:
Originally Posted by rogue View Post
Correct, but the code to detect that condition (when starting a new base) had a bug.
Sorry, I read it as you were only fixing it for newly resumed sieves but you had to restart manually in the fixed version.
henryzz is offline   Reply With Quote
Old 2020-07-02, 16:04   #404
matzetoni
 
matzetoni's Avatar
 
Feb 2019

23×32 Posts
Question k1b2sieve generalization

hey, i've just seen the k1b2sieve! is it possible to generalize this to an arbitrary base b, i.e. giving b as input instead of having b=2 fixed and sieving all b^n+c with n and c in a specified range? (i'd be interested in running such a sieve with base 10)
matzetoni is offline   Reply With Quote
Old 2020-07-02, 18:06   #405
rogue
 
rogue's Avatar
 
"Mark"
Apr 2003
Between here and the

134368 Posts
Default

Quote:
Originally Posted by matzetoni View Post
hey, i've just seen the k1b2sieve! is it possible to generalize this to an arbitrary base b, i.e. giving b as input instead of having b=2 fixed and sieving all b^n+c with n and c in a specified range? (i'd be interested in running such a sieve with base 10)
Yes, but it will be slower and not much faster than using fkbnsieve for each distinct n.
rogue is offline   Reply With Quote
Old 2020-07-02, 19:11   #406
matzetoni
 
matzetoni's Avatar
 
Feb 2019

10010002 Posts
Smile

Quote:
Originally Posted by rogue View Post
Yes, but it will be slower and not much faster than using fkbnsieve for each distinct n.

I see. Still, I'd like to run it over thousands of n, so it would eliminate the hassle of handling thousands of sieve files :)
matzetoni is offline   Reply With Quote
Old 2020-07-03, 06:06   #407
Citrix
 
Citrix's Avatar
 
Jun 2003

112·13 Posts
Default

Quote:
Originally Posted by rogue View Post
Yes, but it will be slower and not much faster than using fkbnsieve for each distinct n.
Since 8+2=10

You can do it by 2 bitshift operations, 1 addition, 3-4 compare operations, 1 subtraction. Still faster than fkbnsieve for each individual n.
Citrix is offline   Reply With Quote
Reply

Thread Tools


All times are UTC. The time now is 03:28.

Mon Sep 28 03:28:06 UTC 2020 up 18 days, 39 mins, 0 users, load averages: 1.49, 1.53, 1.50

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.

This forum has received and complied with 0 (zero) government requests for information.

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation.
A copy of the license is included in the FAQ.