Posts by Tomas Brada

21) Message boards : Number crunching : Проект TBEG недоступен (Message 5321) Posted 26 Feb 2020 by Tomas Brada Post: I agree, The HDD will be tossed. The static system files are installed on raid1 btrfs over a SD-card and the HDD. Btrfs is checksummed filesystem, and it reports no erros, so I know that is not corrupted. The dynamic data files (boinc upload/download and misc) are on btrfs on single over the HDD with metadata dup, again, it's checksummend and reports no errors. The database (boinc results, science results, including the message boards, nextcloud) was on InnoDB on ext4 in writeback over the HDD. InnoDB is checksummed database, and it reported no errors at the time of the backup, so I know the backup is correct. It did report out-of-bounds errors and crashed. SMARTctl did NOT report errors and also InnoDB did NOT report checksum errors, which is strange. I have incremental semi-automatic backups over ssh set up. Even the boot partition was backed up for fast recovery in case of card or disk failure. I had spare card and spare disk on hand. And it did happen once, disk failed back in the alpha stage, but at that time the db and data partitions were small and raided over to the card, so it was quick swap. And that's why I have no spare disk now. The requirements for the disk are minor. It just has to be 2.5" sata. The DB is under 8 gigs and data is under 32 gigs. I am considering getting an SSD instead, because small ssds cost the same as small rust-drives today, but I had bad experience with a similar small SSD. While we are here, the processing finished and will show some stats. The counts include duplicates and disabled groups, but the SPT(24), SPT(17), STPT(16) and TPT(10*2) are rare and exciting. ok=357052 inval=270 Count SPT: 9:1415304 10:0 11:320979 12:15032 13:6131 14:6598462 15:60 16:530544 17:1 18:25702 19:0 20:1314 21:0 22:69 23:0 24:4 Count STPT: 8:40655218 9:0 10:472777 11:0 12:22856 13:0 14:25 15:0 16:2 Count TPT: 6:2107451 7:98346 8:3084 9:88 10:2 # DB select kind k start ofs spt 17 589492143270716899 24 30 60 6 72 12 6 12 spt 24 528050771271601307 14 6 66 6 22 26 4 30 8 4 18 8 spt 24 587950582712698157 2 22 12 6 24 30 14 10 2 54 18 28 spt 24 22930603692243271 70 6 42 18 20 4 18 24 20 16 12 128 tpt 10 3324648277099157 52 16 10 64 10 16 58 22 28 tpt 10 31910610414019031 34 22 94 28 10 10 58 106 46 stpt 16 2640138520272677 2 10 2 16 2 22 2 34
22) Message boards : Number crunching : Проект TBEG недоступен (Message 5319) Posted 26 Feb 2020 by Tomas Brada Post: Hi Timbo! > So, the backup is ok but the server is broken? Yes, the backup is consistent. The baskup imported into my computer also looks OK, it is currently being processed. It is likely a failing disk, but I am not sure. Could also be memory or the mysql software. I need to buy a new disk. > Now the tricky question: When do you think the project will be online again? I am sure that many (including me) have completed tasks that are now just sitting on their computers waiting to be uploaded...maybe you can make a new (temporary) server available and just allow everyone to upload their tasks ? (But not to download new tasks). It will be online when it is done, no ETA. I could enable file uploads, but I would risk corruption of them as well. I will think about it. > And perhaps, you can send out a message via BOINC Manager to let people know what is going on? No, this is not possible right now. Thank you, Timbo, for writing.
23) Message boards : Number crunching : Проект TBEG недоступен (Message 5317) Posted 25 Feb 2020 by Tomas Brada Post: We will see how it turns out. Regarding the backup: I am very sure that my backup of the project is not corrupted. It is the server that is having problems, probably the disk, corrupting the active version of the database. The DB has checksums. Good news: The backup imported on database installed on my computer and SPT results are slowly, but surely, being processed. I will still take a break from working on the server. Maybe a week or two.
24) Message boards : Number crunching : Проект TBEG недоступен (Message 5305) Posted 24 Feb 2020 by Tomas Brada Post: Dear Crunchers and Natalia! Basically, the database was corrupted again. Do not panic! I have very recent backup (few minutes before the incident) and the recently returned results are also archived. I tried to restore the backup, it ran for a few hours and then corrupted again. And then again on another attempt. Additionally, I tried to install mariadb on my PC, and it just refused to work. Thank you crunchers for your contributions. I am very angry about this and I need to take a break.
25) Message boards : Number crunching : About Stop@home project (Message 5235) Posted 10 Feb 2020 by Tomas Brada Post: Вы отсканировали маленький интервал, содержащий только указанные пропущенные решения, чтобы найти специально эти решения? Но пропущенных решений было много из-за данной системной ошибки. Но в дальнейшем поиске пропусков уже не будет (так как вы исправили системную ошибку)? Yes, I only scanned a small interval to find the two missing primes. Now, after I fixed the error, I submitted a larger interval to find the missed tuples. Interval 5e17 is not yet scanned. Какой интервал будет гарантированно без пропусков? From zero up to 21223965000000000. У вас есть БД 12-tuples? Пожалуйста, пришлите её мне; я проверю все 12-tuples своей программой на близнецов. I will. Saving also the k-2*n tuples is still on a todo list, but that is server-side issue. Не поняла, о чём речь. [/quote] I am talking about tbrada/3880. It goes only down to k=16 currently. I need to change the program and re-process the database on the server.
26) Message boards : Number crunching : About Stop@home project (Message 5230) Posted 9 Feb 2020 by Tomas Brada Post: The missing two primes in k=12 list are now there. Because this was a systematic error, I submitted for recalculation the interval scanned so far, but looking specially for that. Saving also the k-2*n tuples is still on a todo list, but that is server-side issue.
27) Message boards : Number crunching : About Stop@home project (Message 5224) Posted 8 Feb 2020 by Tomas Brada Post: The structure around 1856513997898489 is complicated! Expressed as differences and colored. 1856513997898489: 0 10 2 88 2 28 2 88 2 28 2 88 2 10 - SPT(14) 010 2 88 2 28 2 88 2 28 2 88 2 - STPT(12) 010 2 88 2 28 2 88 2 - STPT(8) 130 2 88 2 28 2 88 2 - STPT(8)
28) Message boards : Number crunching : About Stop@home project (Message 5221) Posted 7 Feb 2020 by Tomas Brada Post: Не могу загрузить симметричные 14-tuples :( Несколько попыток с разными значениями i; ничего не получается. выдаётся сообщение, что результаты недоступны. Хотела проверить 16-tuples, тоже не смогла загрузить Это только у меня такая проблема? I improved the performance of that problematic page. But I will need to add a limit parameter. Now it loads after a while. Not always. The "i" parameter is not explained well. Lets see: https://boinc.tbrada.eu/spt_list.php?k=16 This page lists many (255250) solutions. You download it once and have a look at the bottom: 600000724088413891: 0 6 40 42 52 66 78 102 196 220 232 246 256 258 292 298 # last = 21672350 # count = 255250 It says, that last enty in that page (not last on the page, due to sorting), is at ID 21672350. Then next day, you do not have to download all solutions over again, just, the new ones, go to: https://boinc.tbrada.eu/spt_list.php?k=16&i=21672350. And look, already 16 new solutions appeared: 20641275317004581: 0 2 30 98 182 218 222 228 260 266 270 306 390 458 486 488 # last = 21672943 # count = 16 Now last ID is 21672943, use that for i next time. Just keep "i" for each k and kind. This way, duplicates can occur, I am working on that too.
29) Message boards : Number crunching : About Stop@home project (Message 5220) Posted 7 Feb 2020 by Tomas Brada Post: Проверила симметричные шестёрки из близнецов, найденные в проекте TBEG. Их уже много найдено, до моего интервала уже дошли. Показываю начало моего списка решений 1856513997898499: 0 2 90 92 120 122 210 212 240 242 330 332 1865306547706409: 0 2 12 14 42 44 78 80 108 110 120 122 Сравнила, обнаружила нехватку двух моих решений в решениях проекта TBEG, они помечены в моём списке символом . Не сразу сообразила, почему эти решения пропущены в проекте. Но потом возникло такое предположение: эти решения входят ы симметричные 14-tuples. Tomas Brada* моё предположение правильное? Вы не потеряете такие пропущенные решения при создании последовательности OEIS? I checked the DB and there are entries of SPT(14) exactly matching the missing primes you posted. Something may be wrong. I feel so dumb. The error is in my function get_twin_seq_len
30) Message boards : Number crunching : About Stop@home project (Message 5166) Posted 29 Jan 2020 by Tomas Brada Post: Unfortunately, the database at boinc.tbrada.eu suffered a corruption. And about 20 hours of results are lost. Last backup was 2020-01-28 22:23:25. I will restore the backup, but leave the scheduler disabled.
31) Message boards : Number crunching : About Stop@home project (Message 5158) Posted 28 Jan 2020 by Tomas Brada Post: I will try to answer all questions: А что в пропущенном интервале? I am continuing the interval from Stop@home to look for symmetric prime tuples. The application, also looks for others structures (TPT >= 7 pairs, STPT >= 8 primes, gaps) and saves them into DB. I am planning to scan the bottom interval as well, to extend other OEIS sequences. And take over the search XAVER is doing. вы будете искать и не симметричные кортежи из близнецов? Yes. First: as a byproduct of current search and then specifically to fill the gaps. * About twin gaps: Also searching for those, the data coming in, but it needs some post-processing. Everything is clear here. В проекте TBEG найдены следующие решения3 574185979371371531: 0 2 36 38 66 68 108 110 150 152 180 182 216 218 This is worrying. This tuple appears in my database as TPT, but it it symmetric, 34 28 40 40 28 34. There must be error somewhere! I will look into it before starting next batch.
32) Message boards : Number crunching : About Stop@home project (Message 5145) Posted 24 Jan 2020 by Tomas Brada Post: I did not read this forum for a while now. Sorry. But the app is ready! So, good news. Let's go. I need, parameters for the application to run. This includes the Interval and what to look for. You mentioned some large primes here, unfortunately, the app is limited to 2^64-1 or 1.84E19. Here are counts of various structures from batch 56: kind k count(id) spt 13 628 spt 15 7 spt 16 31627 spt 18 1457 spt 20 85 spt 22 7 tpt 6 283894 tpt 7 8201 tpt 8 261 tpt 9 7 stpt 8 36271 stpt 10 64 stpt 12 4
33) Message boards : Number crunching : About Stop@home project (Message 5069) Posted 3 Jan 2020 by Tomas Brada Post: I can add check for largest distance between twins to the application. It is trivial. Очень хорошо. Just to clarify the task here. The application has access to endless sequence of consecutive primes, and derived from those, a sequence of consecutive twin primes. Let p, p+2, q, q+2 be prime such that p+2<q and there are no primes between p+2 and q. The task is to find p, such that q-(p+2) is the largest. Are there other requirements for the primes? Like being part of larger symmetric prime tuple for example?
34) Message boards : Number crunching : About Stop@home project (Message 5053) Posted 31 Dec 2019 by Tomas Brada Post: I can add check for largest distance between twins to the application. It is trivial.
35) Message boards : Number crunching : About Stop@home project (Message 5049) Posted 30 Dec 2019 by Tomas Brada Post: The test of new application version in my project was successful. It found twin prime sequences. We could deploy it right away. But I would like to add a check symmetry as well.
36) Message boards : Number crunching : About Stop@home project (Message 5048) Posted 30 Dec 2019 by Tomas Brada Post: The electric power went out for a while in the night. I used the opportunity to take a full system image of the server. I apologise for the Downtime.
37) Message boards : Number crunching : Проект TBEG недоступен (Message 4972) Posted 13 Dec 2019 by Tomas Brada Post: Back online now! Scheduler is still disabled for maintenance.
38) Message boards : Number crunching : Проект TBEG недоступен (Message 4934) Posted 5 Dec 2019 by Tomas Brada Post: I set up a error page with explanation and link here and set the response code to correctly return 503 for boinc clients.
39) Message boards : Number crunching : Проект TBEG недоступен (Message 4933) Posted 5 Dec 2019 by Tomas Brada Post: I confirm that the project server is offline. I do not know what happened. Even my other server is offline.
40) Message boards : Number crunching : About Stop@home project (Message 4912) Posted 23 Nov 2019 by Tomas Brada Post: I can search for smaller symmetric tuples to find groups of 6 pairs. Could it be useful? Possibly the app can be extended to filter out those tuples that do not have the interesting pairs. Similarly, I could also search for the asymmetric tuples, but I do not understand what they are.

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