Posts by Sergei Chernykh

1) Message boards : Number crunching : Um, Got a Couple of Whoppers? (Message 1589)
Posted 26 Mar 2022 by Sergei Chernykh
Post:
This is temporary, the project is processing the last of 23*13*... numbers where there are more numbers to check per each task. The 23*11k*... range will start soon.
2) Message boards : Number crunching : No new amicable pairs found in 200 WU's. Anyone else? (Message 1573)
Posted 8 Dec 2021 by Sergei Chernykh
Post:
Pairs found each day are listed here: https://sech.me/ap/log/2021/
And the main page is here: https://sech.me/ap/index.html
As far as I can see, you found 9 pairs in 2021 so far.
3) Message boards : Getting started : Unable to add Amicable Numbers project (Message 1546)
Posted 1 Oct 2021 by Sergei Chernykh
Post:
BOINC clients had a problem with site's SSL certificate. I've updated it, so it should work now. Can you try again?
4) Message boards : Number crunching : Unable to upload results (Message 1545)
Posted 1 Oct 2021 by Sergei Chernykh
Post:
It was the problem with site's certificate. Can you try again?
5) Message boards : Bug tracker : Upload server is down (Message 1544)
Posted 1 Oct 2021 by Sergei Chernykh
Post:
I've updated site's SSL certificate to the one that should work according to https://boinc.berkeley.edu/forum_thread.php?id=14413&postid=105557#105557
6) Message boards : Bug tracker : Upload server is down (Message 1542)
Posted 30 Sep 2021 by Sergei Chernykh
Post:
It looks like it's a certificate problem on BOINC client side: https://boinc.berkeley.edu/forum_thread.php?id=14413
BOINC client needs to update ca-bundle.crt
7) Message boards : Number crunching : Um, Got a Couple of Whoppers? (Message 1531)
Posted 18 Jul 2021 by Sergei Chernykh
Post:
If it runs for too long, you can abort it. I'll split all huge tasks into smaller ones and reissue them.
8) Message boards : Number crunching : Um, Got a Couple of Whoppers? (Message 1521)
Posted 10 Jun 2021 by Sergei Chernykh
Post:
Unfortunately there's no way to detect such long tasks until they are actually run. Part of the filtering includes trial division of the larger number in a pair and it can be significantly slower sometimes if many numbers in the range don't have small factors. The range is set for the smaller number in a pair so it's impossible to know in advance what prime factors will be in the larger number.
9) Message boards : Number crunching : Anyone Else Hit A Lull In Finding Amicable Numbers? (Message 1483)
Posted 27 Dec 2020 by Sergei Chernykh
Post:
It depends on current search range of numbers. Some ranges are rich with new numbers, some others don't have them at all.
10) Message boards : News : The search up to 10^21 (Message 1482)
Posted 27 Dec 2020 by Sergei Chernykh
Post:
Would it be possible to get an update on how many pairs you expect there still are to find?

There's still ~2 million undiscovered amicable pairs below 10^21.
11) Message boards : Number crunching : Anyone Else Hit A Lull In Finding Amicable Numbers? (Message 1468)
Posted 27 Nov 2020 by Sergei Chernykh
Post:
It appears the dam has broken, though. I've had my pending tasks queue decrease by a couple of hundred, and my A.N. count has started to climb. Would be interesting to hear from the admin(s) about whether something was constipated :)

Yes, we started the 24*... range yesterday. The previous 25*... range was depleted of new amicable pairs in the end.
12) Message boards : Bug tracker : GTX 1060 3GB - 2 hours and 40% (Message 1453)
Posted 14 Oct 2020 by Sergei Chernykh
Post:
Even 3 GB should be enough, I see GTX 1060 3GB from other users submitting work. Try to reduce kernel size for NVIDIA in project settings.
13) Message boards : Bug tracker : Project not shown in BoincStats (Message 1447)
Posted 20 Sep 2020 by Sergei Chernykh
Post:
All users' stats are exported to https://sech.me/boinc/Amicable/stats/user.gz and you can check yourself that you're in there.
14) Message boards : Number crunching : Rtx 30 series (Message 1441)
Posted 6 Sep 2020 by Sergei Chernykh
Post:
As long as it supports OpenCL (which it does), yes.
15) Message boards : News : The search up to 10^21 (Message 1438)
Posted 2 Sep 2020 by Sergei Chernykh
Post:
I now searching 25*59*... range. Does the second multiplication factor (i.e. 59 and 61) always in descending order? I mean the next range search would be 25*57*..., etc?

Yes, it goes backwards for all factors.
16) Message boards : News : The search up to 10^21 (Message 1435)
Posted 31 Aug 2020 by Sergei Chernykh
Post:
Your found pairs are just sorted in ascending order. The actual search order is based on factorization of the smaller number in a pair. Right now we're in 25*61*... range, still several years away from the end of phase 2.
17) Message boards : Number crunching : Aborted, errored, timed out tasks (Message 1431)
Posted 9 Aug 2020 by Sergei Chernykh
Post:
I've updated Windows mt binary. I'm still not sure why it crashed, but simple recompilation with newer Visual Studio helped.
18) Message boards : Number crunching : Aborted, errored, timed out tasks (Message 1430)
Posted 9 Aug 2020 by Sergei Chernykh
Post:
There seems to be a bug in CPU version there, it crashes for me too.

Edit: it's a compiler bug. The binary crashes, but when I compile it with newer Visual Studio, it doesn't crash.

Edit 2: I'll update the Windows mt binary later today.
19) Message boards : Number crunching : BOINC Pentathlon (Message 1417)
Posted 17 May 2020 by Sergei Chernykh
Post:
It looks like the validation queue will be cleared by the end of today.
20) Message boards : Number crunching : BOINC Pentathlon (Message 1412)
Posted 16 May 2020 by Sergei Chernykh
Post:
I've checked RAID status with mdadm and it's all fine. It seems to be just a high load because of too short WUs.
21) Message boards : Number crunching : BOINC Pentathlon (Message 1410)
Posted 16 May 2020 by Sergei Chernykh
Post:
Nothing else but validator and scheduler is turned on now, but HDD just can't keep up. It didn't happen in the previous two years, I don't know why it's happening now.
22) Message boards : Number crunching : BOINC Pentathlon (Message 1406)
Posted 16 May 2020 by Sergei Chernykh
Post:
It's a 6-core dedicated machine with 64 GB RAM, but the problem is the slow spinning HDD there, sorry! I turned off all non-essential background services, hope it will help.
23) Message boards : Bug tracker : WU'S taking longer (Message 1397)
Posted 11 May 2020 by Sergei Chernykh
Post:
WUs are not all the same due to the nature of the search algorithm. While task generator tries to split the work into equal chunks, it's impossible to predict how much time exactly each WU will take.
24) Message boards : Number crunching : BOINC Pentathlon (Message 1391)
Posted 10 May 2020 by Sergei Chernykh
Post:
The server is ready for this.
25) Message boards : Number crunching : Um, Got a Couple of Whoppers? (Message 1379)
Posted 14 Apr 2020 by Sergei Chernykh
Post:
Yes, this was unusually slow. It's probably related to the nature of the search - some ranges can't be filtered well enough, so more computations per number are needed.
26) Message boards : Number crunching : Um, Got a Couple of Whoppers? (Message 1377)
Posted 13 Apr 2020 by Sergei Chernykh
Post:
Probably because you have RTX 2070 and the other guy has old "Radeon R9 200 Series".
27) Message boards : News : The search up to 10^21 (Message 1371)
Posted 31 Mar 2020 by Sergei Chernykh
Post:
It's a bit too early to talk about this, but here's the search layout:

Phase 1: all odd pairs (m, n) with largest prime factor of m < 1011
Phase 2: all even pairs (m, n) with largest prime factor of m < 1011
Phase 3: all remaining pairs (m, n) with largest prime factor of m > 1011

Phase 3 will take much longer than 1 and 2 combined.
28) Message boards : Number crunching : Um, Got a Couple of Whoppers? (Message 1365)
Posted 24 Mar 2020 by Sergei Chernykh
Post:
This is strange. Your wingmen didn't seem to have any problems with these 2 WUs. Both were running GPU version though.
29) Message boards : Bug tracker : Supermassive WUs all ending in computation errors (Message 1360)
Posted 4 Mar 2020 by Sergei Chernykh
Post:
I just added the second batch and changed status to "part 2", but it actually displays both batches now.
30) Message boards : Bug tracker : Supermassive WUs all ending in computation errors (Message 1358)
Posted 4 Mar 2020 by Sergei Chernykh
Post:
The new batch hasn't started yet. It will have factorizations starting with
2N*...
31) Message boards : Bug tracker : Supermassive WUs all ending in computation errors (Message 1353)
Posted 16 Feb 2020 by Sergei Chernykh
Post:
This was a bug in the task generator, next batch of tasks (2N ranges) will never have tasks with more than ~500 billion numbers to check.
32) Message boards : Bug tracker : large fail rate (Message 1350)
Posted 13 Feb 2020 by Sergei Chernykh
Post:
For some reason your GPU runs out of memory. Do you run more than 1 task per GPU?
33) Message boards : Bug tracker : Factorization '0' is incorrect: 0 is not a prime! (Message 1346)
Posted 5 Feb 2020 by Sergei Chernykh
Post:
This error happens when saved progress ("amicable_checkpoint" file) contains incorrect data or was corrupted somehow. If you get this error again, please check "amicable_checkpoint" in the app directory and post it here.
34) Message boards : Random stuff : Amicable numbers divisible neither 2 nor 3. (Message 1338)
Posted 7 Jan 2020 by Sergei Chernykh
Post:
Here's the list: https://sech.me/ap/coprime_to_6.txt. It's very easy to find such pairs with the current method of search, I just went through all factorization ranges starting with 5N for up to 24-digit numbers. One PC was enough for it.
35) Message boards : Random stuff : Amicable Pairs Discovered (Message 1334)
Posted 29 Dec 2019 by Sergei Chernykh
Post:
There's no fancy interface for this, but all new pairs are logged: https://sech.me/ap/log/2019/2019-12-29/ - start from there and surf between different dates.
36) Message boards : Random stuff : Amicable numbers divisible neither 2 nor 3. (Message 1330)
Posted 20 Dec 2019 by Sergei Chernykh
Post:
Yes, and there is a lot of them. Smallest examples:
X44 Walker&Einstein 2001
5480828320492525=5^2*7^2*11*13*19*31*17*23*103*1319
5786392931193875=5^3*7*11*13*19*31*37*43*61*809

X43 Chernykh 2015
445953248528881275=3^2*5^2*7*13*19*37*43*73*439*22483
659008669204392325=5^2*7*13*19*37*73*571*1693*5839
37) Message boards : Number crunching : GPU version requirements for the search up to 10^20 (Message 1326)
Posted 13 Dec 2019 by Sergei Chernykh
Post:
Because GPU version has to store all prime numbers < 1011 and it can't use compact bit array as CPU version does.
38) Message boards : Bug tracker : badly WU? (Message 1317)
Posted 5 Dec 2019 by Sergei Chernykh
Post:
Yes, looks like it. I'll have to split it into smaller WUs.
39) Message boards : Number crunching : GPU version: kernel size tuning and less UI lags (Message 1314)
Posted 2 Dec 2019 by Sergei Chernykh
Post:
Yes, I'll adjust credit for these tasks.
40) Message boards : News : The search up to 10^21 (Message 1308)
Posted 16 Nov 2019 by Sergei Chernykh
Post:
It should work on 1GB GPUs, but I haven't tested it. You'll probably need to reduce kernel size to the minimum.
41) Message boards : Number crunching : GPU version: kernel size tuning and less UI lags (Message 1305)
Posted 14 Nov 2019 by Sergei Chernykh
Post:
Probably because task size is 68*1012, 100 times more than usual. Task generator was definitely not perfect.
42) Message boards : Number crunching : GPU version: kernel size tuning and less UI lags (Message 1303)
Posted 14 Nov 2019 by Sergei Chernykh
Post:
It doesn't get stuck: https://sech.me/boinc/Amicable/workunit.php?wuid=11804634 - another GPU finished it, you just had to wait a bit more.
43) Message boards : Number crunching : GPU version: kernel size tuning and less UI lags (Message 1296)
Posted 10 Nov 2019 by Sergei Chernykh
Post:
It's not GPU lags in your case, you jut need more than 8 GB system memory to run GPU tasks. Your notebook is swapping and everything starts to lag.
44) Message boards : Number crunching : Missing Computers (Message 1289)
Posted 2 Nov 2019 by Sergei Chernykh
Post:
If they weren't active for more than 90 days then they were deleted automatically.
45) Message boards : News : The search up to 10^20 (Message 1286)
Posted 1 Nov 2019 by Sergei Chernykh
Post:
Yes, it's complete. All previously known amicable numbers were found by the search (which was expected), and many new amicable numbers were found.
46) Message boards : News : The search up to 10^21 (Message 1281)
Posted 30 Oct 2019 by Sergei Chernykh
Post:
No, old tasks will just run out soon. You might abort tasks that use v3.01 GPU application, but it's safe to just leave them running without pausing/resuming.
47) Message boards : News : The search up to 10^21 (Message 1278)
Posted 30 Oct 2019 by Sergei Chernykh
Post:
Attention!
There was a bug in GPU version for 1021 search that caused invalid results after resuming from checkpoint in some cases, so I had to fix it and restart the search from the beginning.
48) Message boards : Bug tracker : Constant Computation errors (Message 1276)
Posted 29 Oct 2019 by Sergei Chernykh
Post:
Error -6 is CL_OUT_OF_HOST_MEMORY. Increase swap file size. You need 8.5 GB per each running GPU task.
49) Message boards : Number crunching : Problem with valid wus count on All Tasks page? (Message 1274)
Posted 29 Oct 2019 by Sergei Chernykh
Post:
Yes, there are usually many amicable numbers found per task now because 1021 search started with the most fruitful ranges.
50) Message boards : Number crunching : Prime Numbers (Message 1271)
Posted 28 Oct 2019 by Sergei Chernykh
Post:
If it takes 1 hour to compute prime table, you're doing something seriously wrong. It usually takes no more than 1 minute and is done on a single CPU core, then it starts using all CPU cores, so it's easy to notice how much time it takes.


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©2022 Sergei Chernykh