IMPORTANT: Overclocking -- including factory overclocking -- on Nvidia GPUs is very strongly discouraged. Even if your GPU can run other tasks without difficulty, it may be unable to run GFN tasks when overclocked.

We now have ten different GFN searches running. This post provides details about what's being searched.

GFNs can be searched by both CPUs and GPUs. There's several variations of both the CPU and GPU transforms which vary greatly by speed and b-limits. CPU transforms come in two flavors:

• 64 bit: This includes the f64 (previously called "default"), SSE2, SSE4, AVX, FMA3, and FMA4 transforms. The fastest available transform is selected automatically by the CPU app.
  
• 80 bit: This is the x87 transform. It has a very high b-limit, but is much slower than the 64 bit transforms.
  

A single CPU app (for each platform) is used that can run all of the transforms.

Note that both 64 bit and 80 bit transforms will run on both 32 bit and 64 bit CPUs.

GPU transforms come in 7 varieties, including two that are deprecated: (Ordered from fastest to slowest)

• CUDA: CUDA has been deprecated and is no longer available from the server.
  
  
• OCL2 (old version): The old OCL2 transform has been deprecated and is no longer available from the server.
  
  
• OCL: This is fastest GPU transform.
  - Requires a GPU with double precision hardware.
  - Runs on both Nvidia and ATI/AMD GPUs.
  - Usually will be skipped on Nvidia Maxwell or newer GPUs
  
  
• OCL4: OCL4 is slower than OCL, but has a higher b-limit. (Previously called "OCL4(low)")
  - OCL4 does NOT require a GPU with double precision hardware.
  - Runs on both Nvidia and ATI/AMD GPUs.
  
  
• OCL5: OCL5 is slower than OCL4, but has a higher b-limit.
  - OCL5 does NOT require a GPU with double precision hardware.
  - Runs on both Nvidia and ATI/AMD GPUs.
  - Usually will be skipped on Nvidia Maxwell or newer GPUs
  
  
• OCL3: OCL3 is slower than OCL5, but has a higher b-limit.
  - OCL3 does NOT require a GPU with double precision hardware.
  - Runs on both Nvidia and ATI/AMD GPUs.
  
  
• OCL2: OCL2 is the GPU equivalent of the 80-bit x87 transform on CPUs. It has a very high b-limit, but is slower than the other GPU transforms.
  - Name disambiguation: The current "OCL2" is the old "OCL4(high)". Only the name has changed. This is NOT the original OCL2 transform.
  - OCL2 does NOT require a GPU with double precision hardware.
  - On an Nvidia GPU, CC 2.0 (Compute Capability) is required. This generally means at least a GTX 4xx series GPU, although there are some exceptions. If you're not sure, you can check on Nvidia's CUDA GPU list and Nvidia's Legacy CUDA GPU list. There's no restriction on ATI/AMD GPUs.
  - Runs on both Nvidia and ATI/AMD GPUs.
  - The current OCL2 (previously called OCL4-high) replaces the original OCL2, which is obsolete. The current OCL2 is significantly faster than the original OCL2 and also has an even higher b-limit.
  

On each platform, there is one app for OCL which combines all the OCL transforms. The combined OCL app will use the fastest available transform (according to GPU type and b-limit), which will usually be in this order:

Nvidia "Maxwell" (or newer) GPUs: OCL4 --> OCL3 --> OCL2
All other GPUs (All AMD GPUs and older Nvidia GPUs): OCL --> OCL4 --> OCL5 --> OCL3 --> OCL2


GFN-15 (32768) status/history has been moved to another thread. Click here to jump directly to GFN-15.

GFN-16 (65536) status/history has been moved to another thread. Click here to jump directly to GFN-16.


n=17 131072 (Low): (as of 8/12/2020)

CPU transform: 80 bit
GPU transform: OCL2 (CC2.0 or better required on Nvidia GPUs)
Optional app via app_info: n/a
Leading edge: 17,110,568
PRPNet status: n/a
BOINC status: ACTIVE
Status: Nominal

Milestone (6/16/2015): Project started on BOINC.
Milestone (7/2/2015): Prime 909548^131072+1 discovered by Van Zimmerman.
Milestone (7/6/2015): Project finished on BOINC at OCL b-limit.
Milestone (10/16/2015): n=17 restarted on BOINC using OCL3.
Milestone (10/27/2015): b=~1,620,000: CPU app transitions from 64 bit to 80 bit.
Milestone (10/27/2015): Prime 1560730^131072+1 discovered by Scott Brown.
Milestone (11/5/2015): Prime 1660830^131072+1 discovered by Sahib.
Milestone (11/10/2015): Prime 1717162^131072+1 discovered by zzuupp.
Milestone (11/10/2015): Prime 1722230^131072+1 discovered by Honza.
Milestone (11/17/2015): Prime 1766192^131072+1 discovered by XSmeagolX.
Milestone (12/12/2015): Prime 1955556^131072+1 discovered by Tabaluga.
Milestone (1/11/2016): Prime 2194180^131072+1 discovered by SosRud.
Milestone (1/20/2016): Prime 2280466^131072+1 discovered by Scott Brown.
Milestone (2/5/2016): Prime 2639850^131072+1 discovered by 288larsson.
Milestone (3/28/16): Switched to new OCL4-low (combined) GPU app.
Milestone (4/2/2016): Prime 3450080^131072+1 discovered by Scott Brown.
Milestone (4/15/2016): Prime 3615210^131072+1 discovered by Scott Brown.
Milestone (5/1/2016): Prime 3814944^131072+1 discovered by Scott Brown.
Milestone (5/16/2016): b=4,045,223: Switch from OCL4 (low) to OCL5 (most GPUs) or OCL3 (Nvidia Maxwell GPUs).
Milestone (5/18/2016): Prime 4085818^131072+1 discovered by Scott Brown.
Milestone (6/4/2016): Prime 4329134^131072+1 discovered by puh32.
Milestone (7/20/2016): Prime 4893072^131072+1 discovered by qbrent.
Milestone (7/29/2016): Prime 4974408^131072+1 discovered by Drainx1.
Milestone (8/27/2016): Prime 5326454^131072+1 discovered by Scott Brown.
Milestone (9/4/2016): Prime 5400728^131072+1 discovered by Scott Brown.
Milestone (9/12/2016): Prime 5471814^131072+1 discovered by rutherfordium.
Milestone (9/24/2016): Prime 5586416^131072+1 discovered by Gator 1-3.
Milestone (10/8/2016): Prime 5734100^131072+1 discovered by PDW.
Milestone (10/21/2016): Prime 5877582^131072+1 discovered by tng*.
Milestone (12/20/2016): Prime 6403134^131072+1 discovered by parabol.
Milestone (12/20/2016): Prime 6391936^131072+1 discovered by Jess.
Milestone (1/20/2017): Prime 6705932^131072+1 discovered by Scott Brown.
Milestone (3/14/2017): Prime 7379442^131072+1 discovered by Scott Brown.
Milestone (4/26/2017): Prime 7832704^131072+1 discovered by 288larsson.
Milestone (4/29/2017): Prime 7858180^131072+1 discovered by Scott Brown.
Milestone (5/5/2017): Prime 7926326^131072+1 discovered by 288larsson.
Milestone (5/22/2017): b=8,076,498: Switch from OCL5 to OCL3.
Milestone (5/31/2017): Prime 8150484^131072+1 discovered by 288larsson.
Milestone (6/25/2017): Switched from OCL3 to OCL2 transform.
Milestone (8/28/2017): Prime 8704114^131072+1 discovered by E. T. Drumm.
Milestone (9/9/2017): Prime 8770526^131072+1 discovered by tng*.
Milestone (11/9/2017): Prime 9240606^131072+1 discovered by DeleteNull.
Milestone (11/15/2017): Prime 9419976^131072+1 discovered by DeleteNull.
Milestone (11/17/2017): Prime 9785844^131072+1 discovered by David Steel.
Milestone (11/18/2017): Prime 9907326^131072+1 discovered by branja.
Milestone (11/18/2017): Prime 10037266^131072+1 discovered by Daniel.
Milestone (11/19/2017): Prime 10368632^131072+1 discovered by nenym.
Milestone (11/19/2017): Prime 10453790^131072+1 discovered by HK-Steve.
Milestone (11/20/2017): Prime 10765720^131072+1 discovered by Ross*.
Milestone (11/26/2017): Prime 10921162^131072+1 discovered by zunewantan.
Milestone (11/28/2017): Prime 10962066^131072+1 discovered by k6xt.
Milestone (11/29/2017): Prime 10994460^131072+1 discovered by Crun-chi.
Milestone (12/2/2017): Prime 11036888^131072+1 discovered by Lumiukko.
Milestone (12/19/2017): Prime 11195602^131072+1 discovered by DoctorNow.
Milestone (12/30/2017): Prime 11267296^131072+1 discovered by rvoskoboynikov.
Milestone (1/1/2018): Prime 11292782^131072+1 discovered by Renix1943.
Milestone (2/18/2018): Prime 11778792^131072+1 discovered by Brucifer.
Milestone (2/27/2018): Prime 11876066^131072+1 discovered by Keith.
Milestone (6/4/2018): Prime 12343130^131072+1 discovered by Robish.
Milestone (6/6/2018): Prime 12357518^131072+1 discovered by yank.
Milestone (7/5/2018): Prime 12512992^131072+1 discovered by MajkPascal.
Milestone (7/31/2018): Prime 12661786^131072+1 discovered by Christian Inci.
Milestone (8/4/2018): Prime 12687374^131072+1 discovered by jpldcon4.
Milestone (9/21/2018): Prime 12851074^131072+1 discovered by E. T. Drumm.
Milestone (10/20/2018): Prime 12961862^131072+1 discovered by tng*.
Milestone (10/24/2018): Prime 12978952^131072+1 discovered by Texas_Connection.
Milestone (11/4/2018): Prime 13083418^131072+1 discovered by CGB.
Milestone (12/24/2018): Prime 13433028^131072+1 discovered by Hooker63.
Milestone (1/6/2019): Prime 13613070^131072+1 discovered by tng*.
Milestone (1/27/2019): Prime 13800346^131072+1 discovered by [AF>Amis des Lapins] Phil1966.
Milestone (2/6/2019): Prime 14020004^131072+1 discovered by 288larsson.
Milestone (2/16/2019): Prime 14217182^131072+1 discovered by vaughan.
Milestone (3/9/2019): Prime 14613898^131072+1 discovered by Kellen.
Milestone (3/25/2019): Prime 14790404^131072+1 discovered by FishFry.
Milestone (4/21/2019): Prime 15091270^131072+1 discovered by k4m1k4z3.
Milestone (4/26/2019): Prime 15147290^131072+1 discovered by dthonon.
Milestone (5/6/2019): Prime 15237960^131072+1 discovered by Johny.
Milestone (5/23/2019): Prime 15342502^131072+1 discovered by tng*.
Milestone (7/1/2019): Prime 15567144^131072+1 discovered by Jewfro.
Milestone (7/12/2019): Prime 15667716^131072+1 discovered by vaughan.
Milestone (7/20/2019): Prime 15731520^131072+1 discovered by tng*.
(As of 7/21/2019, individual GFN-17s will no longer be listed here. You can view them in PrimeGrid's comprehensive prime list.)
Upcoming event: b=42,597,774: End of project when 131072-Low reaches 131072-Mega.


n=17 131072 (Mega): (as of 8/12/2020)

CPU transform: none
GPU transform: OCL2 (CC2.0 or better required on Nvidia GPUs)
Optional app via app_info: n/a
Leading edge: 65,863,208
PRPNet status: n/a
BOINC status: ACTIVE
Status: Nominal.
Comment: This project is GPU-only.
Comment: This search started at b=42,597,774, which is the lowest b such that b^131072+1 has at least one million digits. This search is specifically designed to find mega-primes.

Milestone (10/16/2015): Project started on BOINC.
Milestone (11/9/2015): Mega-Prime 42654182^131072+1 discovered by Nortech. (official announcement)
Milestone (2/24/2016): Mega-Prime 43163894^131072+1 discovered by dem0707. (official announcement)
Milestone (2/25/2016): Mega-Prime 43165206^131072+1 discovered by Freezing. (official announcement)
Milestone (3/28/16): Switched to new OCL4 -high (combined) app.
Milestone (10/5/2016): Mega-Prime 44049878^131072+1 discovered by Alexander Falk. (official announcement)
Milestone (10/14/2016): Mega-Prime 44085096^131072+1 discovered by Alejandro V. Mena. (official announcement)
Milestone (11/26/2016): Mega-Prime 44330870^131072+1 discovered by Doc No. (official announcement)
Milestone (12/11/2016): Mega-Prime 44438760^131072+1 discovered by sangis43. (official announcement)
Milestone (2/1/2017): Mega-Prime 44919410^131072+1 discovered by yank. (official announcement)
Milestone (2/23/2017): Mega-Prime 45315256^131072+1 discovered by Williamd007. (official announcement)
Milestone (3/18/2017): Mega-Prime 45570624^131072+1 discovered by yank. (official announcement)
Milestone (4/26/2017): Mega-Prime 46077492^131072+1 discovered by Novanglus. (official announcement)
Milestone (5/29/2017): Mega-Prime 46371508^131072+1 discovered by Mektacular. (official announcement)
Milestone (5/31/2017): Mega-Prime 46385310^131072+1 discovered by mattozan. (official announcement)
Milestone (6/4/2017): Mega-Prime 46413358^131072+1 discovered by sagiil. (official announcement)
Milestone (7/9/2017): Mega-Prime 46730280^131072+1 discovered by dh1saj. (official announcement)
Milestone (7/10/2017): Mega-Prime 46736070^131072+1 discovered by tng*. (official announcement)
Milestone (7/15/2017): Mega-Prime 46776558^131072+1 discovered by Dingo. (official announcement)
Milestone (8/30/2017): Mega-Prime 47090246^131072+1 discovered by rvoskoboynikov. (official announcement)
Milestone (9/14/2017): Mega-Prime 47179704^131072+1 discovered by AndreiO. (official announcement)
Milestone (1/9/2018): Mega-Prime 48273828^131072+1 discovered by Johnny Rotten.
Milestone (1/18/2018): Mega-Prime 48370248^131072+1 discovered by Gilbert Kalus.
Milestone (2/2/2018): Mega-Prime 48643706^131072+1 discovered by Daniel.
Milestone (2/10/2018): Mega-Prime 49038514^131072+1 discovered by Plšák Ráďa.
Milestone (2/11/2018): Mega-Prime 49090656^131072+1 discovered by eXaPower.
Milestone (2/15/2018): Mega-Prime 49225986^131072+1 discovered by polarbeardj.
Milestone (2/15/2018): Mega-Prime 49243622^131072+1 discovered by mackerel.
Milestone (2/17/2018): Mega-Prime 49331672^131072+1 discovered by [AF>Libristes]cguillem.
Milestone (2/18/2018): Mega-Prime 49397682^131072+1 discovered by Reggie.
Milestone (2/20/2018): Mega-Prime 49530004^131072+1 discovered by DeleteNull.
Milestone (2/26/2018): Mega-Prime 49817700^131072+1 discovered by k4m1k4z3.
Milestone (3/5/2018): Mega-Prime 50055102^131072+1 discovered by Freezing.
Milestone (3/7/2018): Mega-Prime 50110436^131072+1 discovered by DeleteNull.
Milestone (3/10/2018): Mega-Prime 50217306^131072+1 discovered by Robish.
Milestone (3/23/2018): Mega-Prime 50495632^131072+1 discovered by DeleteNull.
Milestone (4/10/2018): Mega-Prime 50844724^131072+1 discovered by dh1saj.
Milestone (4/16/2018): Mega-Prime 50963598^131072+1 discovered by Olgar.
Milestone (5/8/2018): Mega-Prime 51269192^131072+1 discovered by dlawson.
Milestone (5/28/2018): Mega-Prime 51567684^131072+1 discovered by Matthew D Doenges.
Milestone (5/28/2018): Mega-Prime 51570250^131072+1 discovered by DeleteNull.
Milestone (5/28/2018): Mega-Prime 51580416^131072+1 discovered by Honza1616.
Milestone (6/14/2018): Mega-Prime 51872628^131072+1 discovered by DeleteNull.
Milestone (6/18/2018): Mega-Prime 51954384^131072+1 discovered by Robish.
Milestone (6/24/2018): Mega-Prime 52043532^131072+1 discovered by Dirk.
Milestone (7/18/2018): Mega-Prime 52412612^131072+1 discovered by jpldcon4.
Milestone (8/11/2018): Mega-Prime 52712138^131072+1 discovered by Christian Inci.
Milestone (9/2/2018): Mega-Prime 53078434^131072+1 discovered by Landjunge.
Milestone (9/5/2018): Mega-Prime 53161266^131072+1 discovered by IKI.
Milestone (9/24/2018): Mega-Prime 53659976^131072+1 discovered by beijinghouse.
Milestone (10/11/2018): Mega-Prime 54032538^131072+1 discovered by DeleteNull.
Milestone (10/20/2018): Mega-Prime 54161106^131072+1 discovered by IKI.
Milestone (10/23/2018): Mega-Prime 54206254^131072+1 discovered by 288larsson.
Milestone (10/23/2018): Mega-Prime 54212352^131072+1 discovered by IKI.
Milestone (11/1/2018): Mega-Prime 54334044^131072+1 discovered by bcavnaugh.
Milestone (11/3/2018): Mega-Prime 54361742^131072+1 discovered by Honza.
ilestone (11/18/2018): Mega-Prime 54548788^131072+1 discovered by Olgar.
Milestone (12/21/2018): Mega-Prime 55015050^131072+1 discovered by Suzaku Medli.
Milestone (12/31/2018): Mega-Prime 55184170^131072+1 discovered by FishFry.
Milestone (1/3/2019): Mega-Prime 55268442^131072+1 discovered by Wingless Wonder.
Milestone (1/14/2019): Mega-Prime 55579418^131072+1 discovered by bcavnaugh.
Milestone (1/16/2019): Mega-Prime 55645700^131072+1 discovered by bcavnaugh.
Milestone (2/2/2019): Mega-Prime 56307420^131072+1 discovered by recoil44.
Milestone (2/4/2019): Mega-Prime 56383242^131072+1 discovered by Yeti.
Milestone (2/5/2019): Mega-Prime 56459558^131072+1 discovered by emoga.
Milestone (2/7/2019): Mega-Prime 56584816^131072+1 discovered by jpldcon4.
Milestone (2/9/2019): Mega-Prime 56735576^131072+1 discovered by k4m1k4z3.
Milestone (2/11/2019): Mega-Prime 56917336^131072+1 discovered by Azmodes.
Milestone (2/17/2019): Mega-Prime 57438404^131072+1 discovered by bcavnaugh.
Milestone (2/19/2019): Mega-Prime 57594734^131072+1 discovered by dh1saj.
Milestone (2/20/2019): Mega-Prime 57694224^131072+1 discovered by dh1saj.
Milestone (2/20/2019): Mega-Prime 57704312^131072+1 discovered by DeleteNull.
Milestone (2/27/2019): Mega-Prime 58247118^131072+1 discovered by Freezing.
Milestone (3/3/2019): Mega-Prime 58447642^131072+1 discovered by DeleteNull.
Milestone (3/3/2019): Mega-Prime 58447816^131072+1 discovered by DeleteNull.
Milestone (3/5/2019): Mega-Prime 58523466^131072+1 discovered by Dad.
Milestone (3/8/2019): Mega-Prime 58589880^131072+1 discovered by vko.
Milestone (3/31/2019): Mega-Prime 59161754^131072+1 discovered by Frank.
Milestone (4/3/2019): Mega-Prime 59210784^131072+1 discovered by Kellen.
Milestone (4/7/2019): Mega-Prime 59305348^131072+1 discovered by Grind29.
Milestone (4/9/2019): Mega-Prime 59362002^131072+1 discovered by 288larsson.
Milestone (4/11/2019): Mega-Prime 59405420^131072+1 discovered by Skligmund.
Milestone (4/17/2019): Mega-Prime 59515830^131072+1 discovered by Keith.
Milestone (4/22/2019): b=59,575,018 (expected b=~65,450,000): CPUs no longer usable.
Milestone (4/28/2019): Mega-Prime 59692546^131072+1 discovered by CGB.
Milestone (4/29/2019): Mega-Prime 59720358^131072+1 discovered by dh1saj.
Milestone (5/17/2019): Mega-Prime 60133106^131072+1 discovered by darkclown.
Milestone (5/31/2019): Mega-Prime 60455792^131072+1 discovered by k4m1k4z3.
Milestone (6/3/2019): Mega-Prime 60540024^131072+1 discovered by DeleteNull.
Milestone (6/6/2019): Mega-Prime 60642326^131072+1 discovered by DeleteNull.
Milestone (6/19/2019): Mega-Prime 61030988^131072+1 discovered by Johny.
Milestone (6/29/2019): Mega-Prime 61267078^131072+1 discovered by vko.
(As of 7/21/2019, individual GFN-17s will no longer be listed here. You can view them in PrimeGrid's comprehensive prime list.)
Upcoming event: b=400,000,000: End of project when OCL2 limit is reached unless new software is used.
Upcoming event: b=2,000,000,000: End of current sieve file. End of project unless additional sieving is done.


n=18 262144: (as of 8/12/2020)

CPU transform: 80 bit
GPU transform: OCL2
Optional app via app_info: n/a
Leading edge: 9,473,568
PRPNet status: retired
BOINC status: ACTIVE
Status: Nominal.

Milestone (6/9/2010): Project started on PRPNet.
Milestone (2/8/2011): Mega-Prime 145310^262144+1 discovered by MiHost on PRPNet. (official announcement)
Milestone (3/8/2011): Mega-Prime 40734^262144+1 discovered by s-yama on PRPNet. (official announcement)
Milestone (10/29/2011): Mega-Prime 361658^262144+1 discovered by MichelJohnson on PRPNet. (official announcement)
Milestone (1/8/2012): Moved from PRPNet to BOINC.
Milestone (1/18/2012): Mega-Prime 525094^262144+1 discovered by KWSN Raw Data. (official announcement)
Milestone (2/12/2012): Mega-Prime 676754^262144+1 discovered by Usucapio Libertatis. (official announcement)
Milestone (2/23/2012): Moved from BOINC to PRPNet.
Milestone (4/19/2012): Mega-Prime 773620^262144+1 discovered by s-yama on PRPNet. (official announcement)
Milestone (7/6/2015): Double check of PRPNet work started on BOINC.
Milestone (8/2/2015): Double check of PRPNet work complete.
Milestone (11/4/2015): Moved to BOINC from PRPNet starting with double check of recent PRPNet tests.
Milestone (12/5/2015): b=~1,350,000: CPU app transitions from 64 bit to 80 bit.
Milestone (12/6/2015): b=1,256,802: Double check ends and new work begins.
Milestone (2/16/2016): Mega-Prime 1415198^262144+1 discovered by boss. (official announcement)
Milestone (3/5/2016): Mega-Prime 1488256^262144+1 discovered by 288larsson. (official announcement)
Milestone (3/28/16): Switched to new OCL4-low (combined) GPU app.
Milestone (5/4/2016): Mega-Prime 1615588^262144+1 discovered by brinktastee. (official announcement)
Milestone (8/10/2016): Mega-Prime 1828858^262144+1 discovered by brinktastee. (official announcement)
Milestone (11/24/2016): Mega-Prime 2042774^262144+1 discovered by motsu. (official announcement)
Milestone (2/24/2017): Mega-Prime 2514168^262144+1 discovered by wdethomas. (official announcement)
Milestone (3/11/2017): Mega-Prime 2611294^262144+1 discovered by Tabaluga. (official announcement)
Milestone (3/22/2017): Mega-Prime 2676404^262144+1 discovered by DeleteNull. (official announcement)
Milestone (5/11/2017): b=2,860,404: Switch from OCL4 to OCL5 or OCL3.
Milestone (6/30/2017): Mega-Prime 3060772^262144+1 discovered by No.15. (official announcement)
Milestone (10/30/2017): Mega-Prime 3547726^262144+1 discovered by Scott Brown. (official announcement)
Milestone (11/16/2017): Mega-Prime 3596074^262144+1 discovered by [PST]Howard. (official announcement)
Milestone (12/3/2017): Mega-Prime 3673932^262144+1 discovered by No.15. (official announcement)
Milestone (1/10/2018): Mega-Prime 3853792^262144+1 discovered by rjs5. (official announcement)
Milestone (1/27/2018): Mega-Prime 3933508^262144+1 discovered by Freezing. (official announcement)
Milestone (2/15/2018): Mega-Prime 4246258^262144+1 discovered by Robish. (official announcement)
Milestone (3/1/2018): Mega-Prime 4489246^262144+1 discovered by DeleteNull. (official announcement)
Milestone (6/5/2018): Mega-Prime 5152128^262144+1 discovered by Robish. (official announcement)
Milestone (6/17/2018): Mega-Prime 5205422^262144+1 discovered by Scott Brown. (official announcement)
Milestone (9/12/2018):: b=5,710,946: Switch from OCL5 to OCL3.
Milestone (9/26/2018): Mega-Prime 5828034^262144+1 discovered by Robish. (official announcement)
Milestone (10/11/2018): b=5,931,641: Switch from OCL3 to OCL2.
Milestone (12/12/2018): Mega-Prime 6287774^262144+1 discovered by Olgar. (official announcement)
Milestone (12/14/2018): Mega-Prime 6291332^262144+1 discovered by KFR. (official announcement)
Milestone (9/9/2019): Mega-Prime 8521794^262144+1 discovered by jpldcon4. (official announcement)
Milestone (11/6/2019): Mega-Prime 8883864^262144+1 discovered by rjs5. (official announcement)
Milestone (12/5/2019): Mega-Prime 9125820^262144+1 discovered by yoshi. (official announcement)
Milestone (1/21/2020): Mega-Prime 9450844^262144+1 discovered by Eikelenboom. (official announcement)
Milestone (2/12/2020): Mega-Prime 9750938^262144+1 discovered by Freezing. (official announcement)
Milestone (2/16/2020): Mega-Prime 9812766^262144+1 discovered by tng. (official announcement)
(As of 3/1/2020, individual GFN-18s will no longer be listed here. You can view them in PrimeGrid's comprehensive prime list.)
Upcoming event: b=~54,080,000: CPUs no longer usable.
Upcoming event: b=400,000,000: End of project when OCL2 limit is reached unless new software is used.
Upcoming event: b=2,000,000,000: End of current sieve file. End of project unless additional sieving is done.


n=19 524288: (as of 8/12/2020)

CPU transform: 80 bit
GPU transform: OCL5 or OCL3
Optional app via app_info: n/a
Leading edge: 3,809,098
PRPNet status: retired
BOINC status: ACTIVE
Status: Nominal.

Milestone (6/9/2010): Project started on PRPNet.
Milestone (11/19/2011): Mega-Prime 75898^524288+1 discovered by Michael Goetz on PRPNet. (official announcement)
Milestone (2/23/2012): Project moved from PRPNet to BOINC.
Milestone (6/15/2012): Mega-Prime 341112^524288+1 discovered by Peyton Hayslette. (official announcement)
Milestone (6/20/2012): Mega-Prime 356926^524288+1 discovered by bherbihyewrbg. (official announcement)
Milestone (8/8/2012): Mega-Prime 475856^524288+1 discovered by ragnarag. (official announcement)
Milestone (11/29/2012): Moved from BOINC to PRPNet at end of CUDA limit.
Milestone (8/2/2015): Double check of PRPNet work started on BOINC.
Milestone (9/15/2015): Double check of PRPNet work completed.
Milestone (11/4/2015): Moved to BOINC from PRPNet starting with double check of recent PRPNet tests.
Milestone (12/20/2015): b=920,574: Double check ends and new work begins.
Milestone (3/28/2016): Switched to new OCL4-low (combined) GPU app.
Milestone (6/1/2016): b=~1,100,000: CPU app transitions from 64 bit to 80 bit.
Milestone (1/15/2018): Mega-Prime 1880370^524288+1 discovered by Scott Brown. (official announcement)
Milestone (3/5/2018): b=2,022,611: Switch from OCL4 to OCL5 or OCL3.
Milestone (3/20/2018): Mega-Prime 2061748^524288+1 discovered by Cesare Marini. (official announcement)
Milestone (8/4/2018): Mega-Prime 2312092^524288+1 discovered by Robish. (official announcement)
Milestone (3/18/2019): Mega-Prime 2733014^524288+1 discovered by Yair Givoni. (official announcement)
Milestone (4/17/2019): Mega-Prime 2788032^524288+1 discovered by BlisteringSheep. (official announcement)
Milestone (6/29/2019): Mega-Prime 2877652^524288+1 discovered by Tabaluga. (official announcement)
Milestone (9/18/2019): Mega-Prime 2985036^524288+1 discovered by eXaPower. (official announcement)
Milestone (12/24/2019): Mega-Prime 3214654^524288+1 discovered by Freezing. (official announcement)
Milestone (5/29/2020): Mega-Prime 3638450^524288+1 discovered by DeleteNull. (official announcement)
Upcoming event: b=4,038,249: Switch from OCL5 to OCL3.
Upcoming event: b=4,194,304: Switch from OCL3 to OCL2.
Upcoming event: b=~43,620,000: CPUs no longer usable.
Upcoming event: b=400,000,000: End of project when OCL2 limit is reached unless new software is used.
Upcoming event: b=2,000,000,000: End of current sieve file. End of project unless additional sieving is done.


n=20 1048576: (as of 8/12/2020)

CPU transform: 80 bit
GPU transform: OCL5 or OCL3
Optional app via app_info: n/a
Leading edge: 1,453,812
PRPNet status: n/a
BOINC status: ACTIVE
Status: Nominal.

Milestone (11/29/2012): Project started on BOINC.
Milestone (6/16/2015): Project finished on BOINC (reached OCL limit).
Milestone (11/4/2015): Restarted on BOINC using OCL3.
Milestone (3/28/2016): Switched to new OCL4-low (combined) GPU app.
Milestone (7/9/2017): b=~900,000: CPU app transitions from 64 bit to 80 bit.
Milestone (8/29/2017): Mega-Prime 919444^1048576+1 discovered by Van Zimmerman. (official announcement)
Milestone (10/31/2018): Mega-Prime 1059094^1048576+1 discovered by Robish. (official announcement)
Milestone (8/12/2020): b=1,430,202: Switch from OCL4 to OCL5 or OCL3.
Upcoming event: b=2,855,473: Switch from OCL5 to OCL3.
Upcoming event: b=2,965,821: Switch from OCL3 to OCL2.
Upcoming event: b=~36,300,000: CPUs no longer usable.
Upcoming event: b=100,000,000: End of current sieve file. End of project unless additional sieving is done.
Upcoming event: b=400,000,000: End of project when OCL2 limit is reached.


n=21 2097152: (as of 8/12/2020)

CPU transform: 64 bit
GPU transform: OCL (Double Precision GPU REQUIRED), or OCL4
Optional app via app_info: n/a
Leading edge: 607,918
PRPNet status: n/a
BOINC status: ACTIVE
Status: Nominal.
Comment: GeneferOCL will use whichever GPU transform is fastest. On AMD and older Nvidia GPUs, this is usually OCL. On newer Nvidia GPUs (Maxwell or later), this is usually OCL4.

Milestone (9/15/2015): Project started on BOINC.
Milestone (3/28/16): Switched to new combined OCL app which allows for faster OCL4(low) to be used automatically on "Maxwell" GPUs.
Upcoming event: b=~660,000: Switch from OCL to OCL4.
Upcoming event: b=~730,000: CPU app transitions from 64 bit to 80 bit.
Upcoming event: b=1,011,306: Switch from OCL4 to OCL5 or OCL3.
Upcoming event: b=2,019,124: Switch from OCL5 to OCL3.
Upcoming event: b=2,097,152: Switch from OCL3 to OCL2.
Upcoming event: b=~29,740,000: CPUs no longer usable.
Upcoming event: b=400,000,000: End of project when OCL2 limit is reached unless new software is used.
Upcoming event: b=2,000,000,000: End of current sieve file. End of project unless additional sieving is done.


n=22 4194304: (as of 8/12/2020)

CPU transform: none
GPU transform: OCL (Double Precision GPU REQUIRED) or OCL4
Optional app via app_info: n/a
Leading edge: 176,336
PRPNet status: n/a
BOINC status: ACTIVE
Status: Nominal. originally designed to search for the world's largest known prime, but can now only find the fourth largest known prime.
Comment: This project is GPU-only.
Comment: GeneferOCL will use whichever GPU transform is fastest. On AMD and older Nvidia GPUs, this is usually OCL. On newer Nvidia GPUs (Maxwell or later), this is usually OCL4.

Milestone (2/24/2012): Project started on BOINC.
Milestone (11/3/2015): CPU tasks enabled.
Milestone (3/28/2016): Switched to new combined OCL app which allows for faster OCL4(low) to be used automatically on "Maxwell" GPUs.
Milestone (2/25/2017): CPU tasks disabled. (Too slow on most CPUs.)
Milestone (1/21/2020): CPU tasks enabled. (Only recommended for computers running 24/7)
Upcoming event: b=~540,000: Switch from OCL to OCL4.
Upcoming event: b=~610,000: CPU app transitions from 64 bit to 80 bit.
Upcoming event: b=715,101: Switch from OCL4 to OCL5 or OCL3.
Upcoming event: b=846,398: End of project when b reaches the starting point of Do You Feel Lucky?


Do You feel Lucky? (Genefer World Record, n=22 and b>=846,398): (as of 8/12/2020)

CPU transform: none
GPU transform: OCL5 or OCL3
Optional app via app_info: n/a
Leading edge: 910,908
PRPNet status: n/a
BOINC status: ACTIVE
Status: Nominal. Specifically designed to search for the world's largest known prime. Search range will be adjusted as needed to always be searching for a world record prime.
Comment: This project is GPU-only.
Comment: GeneferOCL will use whichever GPU transform is fastest. This is usually OCL5 but may sometimes be OCL3.

Milestone (2/1/2019): Project started on BOINC with b=846,404.
Upcoming event: b=1,427,737: Switch from OCL5 to OCL3.
Upcoming event: b=1,482,910: Switch from OCL3 to OCL2.
Upcoming event: b=~24,100,000: CPUs no longer usable.
Upcoming event: b=400,000,000: End of project when OCL2 limit is reached unless new software is used.
Upcoming event: b=2,000,000,000: End of current sieve file. End of project unless additional sieving is done.
____________

Stderr asks me to ensure my GPU is capable. Well, yes, it is, according to every other OCL task I've ever run on any project with decent developers, so...

Did I miss something?

Double precision is NOT required on the GPUs for either OCL2 or OCL3. That not only means that a wider variety of ATI/AMD GPUs may be used, but it also means if you have a GTX TITAN you can run it in its higher clock speed mode rather than double precision mode.

Stderr asks me to ensure my GPU is capable. Well, yes, it is, according to every other OCL task I've ever run on any project with decent developers, so...

Did I miss something?

My guess would be that 32768 tasks are running using OCL3 whereas 65536 tasks are using OCL.

As per Mike's yesterdays post here:

Double precision is NOT required on the GPUs for either OCL2 or OCL3. That not only means that a wider variety of ATI/AMD GPUs may be used, but it also means if you have a GTX TITAN you can run it in its higher clock speed mode rather than double precision mode.

HD 6850 has no double precision.

Thank you for deleting/moving my post without notification.

I also appreciate the use, in your explanation(s), of mathematical terminology with which I'm not explicitly familiar. If the answer to my question really must reference my inability to differentiate between different "types" of OCL dependencies, well, I'm terribly sorry for missing the part where the Preferences indicate I need a specific GPU (in this case, the significantly more useful 6950/70 or better...) Actually, I'm not sorry, because the Preferences page says nothing of the sort.

Please make an effort to better explain specific application requirements in the "Preferences" area rather than simply placing a check box under "OpenCL."

size-10 font

It does not help that ALL of these tasks are simply lumped under the "Genefer" sub-project.

Brand new ranges have opened up for GFN n=15, 16 and 17. Well done Admins! That couldn't have been easy.
I ran the stats on these new ranges for expected number of primes for Transforms up to their "B" limits:

GPU OCL3
n = 15, b = 10,428,486 thru 16,777,216 expect 68 primes
n = 16, b = 4,205,312 thru 11,863,283 expect 82 primes
n = 17, b = 1,322,216 thru 8,388,608 expect 38 primes

GPU OCL2
n = 15, b = 16,777,216 thru 95,520,000 expect 786 primes
n = 16, b = 11,863,283 thru 81,670,000 expect 680 primes
n = 17, b = 8,388,608 thru 42,597,772 expect 169 primes
n = 17, b = 42,597,774 thru 60,430,000 expect 84 Mega primes

CPU 64-bit
n = 17, b = 1,322,216 thru 1,620,000 expect 1.76 primes

CPU 80-bit
n = 15, b = 10,428,486 thru 99,460,000 expect 892 primes
n = 16, b = 4,205,312 thru 79,010,000 expect 737 primes
n = 17, b = 1,620,000 thru 64,150,000 expect 308 primes (101 of them Mega)

That should give you an idea how large some of these ranges are.
OCL3 ranges should be all complete in 6 months, OCL2 in a couple of years.
Residual bit of CPU 80-bit beyond the reach of OCL2 will take a few more years.

CPU 64-bit
n = 17, b = 1,322,216 thru 1,620,000 expect 1.76 primes

CPU 64-bit
n = 17, b = 1,322,216 thru 1,620,000 expect 1.76 primes

Aww, so few? Any indication of how many candidates there are in that range? I was rather hoping for more than 2 primes!

I hadn't thought to look for already known primes in that range, since there was an earlier statement that this is a new range being tested. The largest two b would be in the range we're about to test. So are the 1.76 primes expected new ones in addition to those?

It also raises the question, has that range been covered already, or were they found by other means? That is, other than specifically searching in the way we are. I also note they were discovered a long time ago.

I hadn't thought to look for already known primes in that range, since there was an earlier statement that this is a new range being tested. The largest two b would be in the range we're about to test. So are the 1.76 primes expected new ones in addition to those?

It also raises the question, has that range been covered already, or were they found by other means? That is, other than specifically searching in the way we are. I also note they were discovered a long time ago.

Thanks for the links and the history lesson. All the more impressive that this was done over 10 years ago.

I know things in statistics need to be interpreted with some caution when looking at ever smaller ranges, but I'll have to have a play with some numbers there.

Prime numbers are not random but are like a rare event process!

The expected number of primes is a priori which is different from the a posteriori number of primes.

1.24 primes are expected in 700,000-900,000 and there are none, 0.12 are expected in 1,360,000-1,380,000 and two were found.

Our intuition is wrong with rare events. If an event occurs about every year, it will occur four times over the same year every century. People (commentators) think that something changed but this is just the Poisson distribution.
The prime number search helps us to understand better this sort of non-intuitive events.

1.24 primes are expected in 700,000-900,000 and there are none, 0.12 are expected in 1,360,000-1,380,000 and two were found.

Just wondering... what about n =< 14 and n => 22, any reason as to why 15-21 are offered?

Just wondering... what about n =< 14 and n => 22, any reason as to why 15-21 are offered?

The original post in this thread is quite simply a masterpiece. How often will this info be updated? I am the furthest thing from a math whiz but would like to educate myself as to what all these terms mean without flooding this thread or others with a bunch of noob questions. Is there an external source that would be a good place to start?

Just wondering... what about n =< 14 and n => 22, any reason as to why 15-21 are offered?

Just wondering... what about n =< 14 and n => 22, any reason as to why 15-21 are offered?

n=23 is HUGE -- assume the run times would be 4 times as long as the n=22 world record tasks. Have you run any world record tasks yet?

Just wondering... what about n =< 14 and n => 22, any reason as to why 15-21 are offered?

n=23 is HUGE -- assume the run times would be 4 times as long as the n=22 world record tasks. Have you run any world record tasks yet?

Yes, I've run WR before. ~90h with OCL3 (almost finished) and I think ~130h with CUDA on my Gtx 970. But, given that no work seems to be done, wouldn't B start "small" enough to be worth it to make the tasks not as long?

Just wondering... what about n =< 14 and n => 22, any reason as to why 15-21 are offered?

If really adventurous, one can choose a low n and the sieving and test alone.

If really adventurous, one can choose a low n and the sieving and test alone.

Be afraid. I was thinking that!

What has been done before? I saw this: http://yves.gallot.pagesperso-orange.fr/primes/results.html

What software do we have? I see in the CPU genefer it can report supported b ranges. This started at n=8 (256).

Ok, let's look more at n=8 then. From the above link it has been tested b < 7M. That sounded big, until I tried to work out the decimal digit size. If I'm not mistaken, that would be approximated by 256 * log10(b). That doesn't figure in the "+1" which would be insignificant, and I don't know how to! Anyway, how big would a number be at b = 7M? 1753 digits. That's tiny. Ok, other way around, how big do we have to go before it gets more interesting? To reach Top 5000 list at the moment would need a size greater than 388340 digits. With b at 1T, we're only up to 3072 digits. Not even close. Genefer with x87 transform runs out of steam at 452M anyway.

I think we can write off n=8 unless you're really bored. A value of n at the upper end <15 might be more interesting. Again from the earlier link, it looks like n=13 and 14 were only single pass tested. Perhaps replicating that would be a test of ability, before continuing onwards above it. The upper b tested for n=14 at 2.7M would result in a 103572 digit number. So still quite small by current standards and should be fast to test, and it looks like CPU genefer can do that with fma3 transform.

Am I crazy enough?

Math (particularly logarithms) being what it is, there's no way for n's below 16 to ever make the T5K list again, at least using Genefer. With n=15 (which at one time was large enough for the list), you would need b of 709,898,549,924 (709 billion) which is way, way beyond the ability of any version of Genefer. You could do it with LLR if you really wanted to.

With even smaller n's, it just gets worse. Much, much worse. Really quickly.

At n=14 (16384), you need b>=503,955,951,184,464,000,000,000
At n=13 (8192), you need b>=253,971,600,734,238,000,000,000,000,000,000,000,000,000,000,000
At n=12 (4096), you need b>=64,501,573,979,511,100,000,000,000,000,000,000,000,...
000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000
At n=11 (2048), you need b>=4,160,453,045,834,350,000,000,000,000,000,000,000,000,000,000,000,000,000,...
000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,...
000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,...
000,000,000,000,000,000,000
At n=10 (1024), Excel gives up with a numeric overflow. :)
____________
My lucky number is 75898⁵²⁴²⁸⁸+1

What software do we have? I see in the CPU genefer it can report supported b ranges. This started at n=8 (256).

I did have a quick play to size up the job and see how much computational work it was. Got a sieve started just to replicate the n=14 range of b up to 2.7M. Didn't take long to whittle that down to 600k candidates and still dropping before I stopped. Running genefer on the biggest unit in that range took about 21 seconds, while my CPU was already running 4 other tasks. That puts the estimated time required at around 145 core days but I'm sure that would still drop a lot more from having dedicated cores and working out where optimal sieve is.

Found the cuda sieve (forgot the exact name) but that only seems to work on n>=15. When I ran some low b through genefer to see what happens, surprised to find the very first test 2^16384+1 was PRP, which Proth later confirmed was composite. Haven't looked at PFGW at all yet.

None of this might have any use beyond personal interest, but I'm finding it an interesting learning exercise on how the different bits of software handle and are used together.

At the moment I'm debating if this is worth continuing on some offline boxes I have access to.

Found the cuda sieve (forgot the exact name) but that only seems to work on n>=15. When I ran some low b through genefer to see what happens, surprised to find the very first test 2^16384+1 was PRP, which Proth later confirmed was composite. Haven't looked at PFGW at all yet.

btw, are we 3 years without any new Genefer megaprime?

The WR tasks aren't too bad with the right hardware. I'm crunching at a rate of 11 WUs/week, and as soon as one machine finishes some ocl2 test units, that should go to just under 17.

I'd be happy to point my machines at n=23 tasks if they were available. Particularly once the n=22 b gets too large to run straight ocl.

Just wondering... what about n =< 14 and n => 22, any reason as to why 15-21 are offered?

n=23 is HUGE -- assume the run times would be 4 times as long as the n=22 world record tasks. Have you run any world record tasks yet?

As for the smaller numbers, there's a lot of reasons we're not running them. The GPU apps for both sieving and Genefer are less efficient on such small n's. We don't have a lot of sieving done for very low n's (possibly NO sieving at all.) It's not clear there's a demand for such work. The vast number of tiny tasks would be a problem for the server. And that's just the reasons that immediately come to mind.

I'd be happy to point my machines at n=23 tasks if they were available. Particularly once the n=22 b gets too large to run straight ocl.

I've switched the n=16 (65536) OpenCL app from OCL to OCL3.
____________
My lucky number is 75898⁵²⁴²⁸⁸+1

My AMD 1100T CPU is now performing 5 out of 5 GFN 17 Low with x87 Transform.
With SSE2 Transform I was doing one WU per core in under 2 hours.
WU with x87 takes around 13 hours.
So I am moving my 1100T cores away from GFN 17 Low to chase sieving sub-project badge levels, where AMD cores are relatively competitive.

I also have a 2 core i7-3540M laptop CPU, still using AVX Transform, one WU in about 35min.
Getting the odd WU using x87 Transform, one in about 1hr50min.
I'll keep this CPU on GFN 17 Low for the moment.

GFN 17 Low leading edge now past 1,530,000.

My AMD 1100T CPU is now performing 5 out of 5 GFN 17 Low with x87 Transform.
So I am moving my 1100T cores away from GFN 17 Low to chase sieving sub-project badge levels

My AMD 1100T CPU is now performing 5 out of 5 GFN 17 Low with x87 Transform.
So I am moving my 1100T cores away from GFN 17 Low to chase sieving sub-project badge levels

GFN16 still have lot of CPU work available (current edge = 1640K, expected switch to x87 near 2000K). Want to help clean it up?

My AMD 1100T CPU is now performing 5 out of 5 GFN 17 Low with x87 Transform.
So I am moving my 1100T cores away from GFN 17 Low to chase sieving sub-project badge levels

GFN16 still have lot of CPU work available (current edge = 1640K, expected switch to x87 near 2000K). Want to help clean it up?

My GPU is currently offline. Crashing under load. [...] I've dropped to 31st place on number of GFN WUs processed :-(

My AMD 1100T CPU is now performing 5 out of 5 GFN 17 Low with x87 Transform.
So I am moving my 1100T cores away from GFN 17 Low to chase sieving sub-project badge levels

GFN16 still have lot of CPU work available (current edge = 1640K, expected switch to x87 near 2000K). Want to help clean it up?

My GPU is currently offline. Crashing under load. [...] I've dropped to 31st place on number of GFN WUs processed :-(

So... why not put your 1100 _CPU_ cores to GFN16 then instead of sieving? Don't miss the chance, limited opportunity, only few days left! :) x87 transition is expected in about a week at current rates.

Upcoming event: b=~1,990,000: CPU app transitions from 64 bit to 80 bit.

GFN-16, b = 1833000, got first switches from FMA to AVX. It still can continue in AVX mode, but this will not stay long. The last fast CPU GFN range is coming to the end.

BTW why AVX is more precise then FMA? Shouldn't they use same hardware? Is FMA opcode (single command) introduces more rounding errors then same calculations done manually in few separate commands, or some other reason exist?

GFN-16, b = 1833000, got first switches from FMA to AVX. It still can continue in AVX mode, but this will not stay long. The last fast CPU GFN range is coming to the end.

Using FMA3 transform
Starting initialization...
Initialization complete (0.055 seconds).
Testing 1816532^65536+1...
Estimated time remaining for 1816532^65536+1 is 0:05:54

maxErr exceeded for 1816532^65536+1, 0.4531 > 0.4500
maxErr exceeded while using FMA3; switching to AVX (Intel).
Using AVX (Intel) transform
Resuming 1816532^65536+1 from a checkpoint (487423 iterations left)
Estimated time remaining for 1816532^65536+1 is 0:03:03

Successful computation progress with AVX (Intel); switching back to FMA3.
Using FMA3 transform
Resuming 1816532^65536+1 from a checkpoint (385023 iterations left)
Estimated time remaining for 1816532^65536+1 is 0:01:40
1816532^65536+1 is complete. (410206 digits) (err = 0.4062) (time = 0:06:42) 06:10:56

BTW why AVX is more precise then FMA? Shouldn't they use same hardware? Is FMA opcode (single command) introduces more rounding errors then same calculations done manually in few separate commands, or some other reason exist?

It's even more complicated. These are two Intel AVX CPUs on the same workunit. They're not identical CPUs, however. But one's Windows, the other is Mac. Different compilers.

Windows:

genefer 3.2.9 (Windows/CPU/64-bit)
Supported transform implementations: avx-intel sse4 sse2 default x87
Copyright 2001-2015, Yves Gallot
Copyright 2009, Mark Rodenkirch, David Underbakke
Copyright 2010-2012, Shoichiro Yamada, Ken Brazier
Copyright 2011-2015, Iain Bethune, Michael Goetz, Ronald Schneider
Genefer is free source code, under the MIT license.

Command line: projects/www.primegrid.com/primegrid_genefer_3_2_9_3.09_windows_x86_64__cpuGFN16.exe -boinc -q 1784630^65536+1

Priority change succeeded.
Using AVX (Intel) transform
Starting initialization...
Initialization complete (0.159 seconds).
Testing 1784630^65536+1...
Estimated time remaining for 1784630^65536+1 is 0:15:58
1784630^65536+1 is complete. (409702 digits) (err = 0.4062) (time = 0:16:00) 12:12:27

genefer 3.2.9 (Apple-x86/CPU/64-bit)
Supported transform implementations: avx-intel sse4 sse2 default x87
Copyright 2001-2015, Yves Gallot
Copyright 2009, Mark Rodenkirch, David Underbakke
Copyright 2010-2012, Shoichiro Yamada, Ken Brazier
Copyright 2011-2015, Iain Bethune, Michael Goetz, Ronald Schneider
Genefer is free source code, under the MIT license.

Command line: primegrid_genefer_3_2_9_3.09_x86_64-apple-darwin__cpuGFN16 -boinc -q 1784630^65536+1

Priority change succeeded.
Using AVX (Intel) transform
Starting initialization...
Initialization complete (0.071 seconds).
Testing 1784630^65536+1...
Estimated time remaining for 1784630^65536+1 is 0:07:18

maxErr exceeded for 1784630^65536+1, 0.4688 > 0.4500
maxErr exceeded while using AVX (Intel); switching to SSE4.
Using SSE4 transform
Resuming 1784630^65536+1 from a checkpoint (446463 iterations left)
Estimated time remaining for 1784630^65536+1 is 0:04:30

Successful computation progress with SSE4; switching back to AVX (Intel).
Using AVX (Intel) transform
Resuming 1784630^65536+1 from a checkpoint (413695 iterations left)
Estimated time remaining for 1784630^65536+1 is 0:02:25

maxErr exceeded for 1784630^65536+1, 0.4688 > 0.4500
maxErr exceeded while using AVX (Intel); switching to SSE4.
Using SSE4 transform
Resuming 1784630^65536+1 from a checkpoint (413695 iterations left)
Estimated time remaining for 1784630^65536+1 is 0:04:15

Successful computation progress with SSE4; switching back to AVX (Intel).
Using AVX (Intel) transform
Resuming 1784630^65536+1 from a checkpoint (364543 iterations left)
Estimated time remaining for 1784630^65536+1 is 0:02:07

maxErr exceeded for 1784630^65536+1, 0.4688 > 0.4500
maxErr exceeded while using AVX (Intel); switching to SSE4.
Too many errors with AVX (Intel); Calculation will proceed using only more accurate transforms.
Using SSE4 transform
Resuming 1784630^65536+1 from a checkpoint (364543 iterations left)
Estimated time remaining for 1784630^65536+1 is 0:03:40

maxErr exceeded for 1784630^65536+1, 0.4531 > 0.4500
maxErr exceeded while using SSE4; switching to SSE2.
Using SSE2 transform
Resuming 1784630^65536+1 from a checkpoint (65535 iterations left)
Estimated time remaining for 1784630^65536+1 is 0:00:49

maxErr exceeded for 1784630^65536+1, 0.4531 > 0.4500
maxErr exceeded while using SSE2; switching to Default.
Using Default transform
Resuming 1784630^65536+1 from a checkpoint (65535 iterations left)
Estimated time remaining for 1784630^65536+1 is 0:01:33

maxErr exceeded for 1784630^65536+1, 0.4844 > 0.4500
maxErr exceeded while using Default; switching to x87 (80-bit).
Using x87 (80-bit) transform
Resuming 1784630^65536+1 from a checkpoint (65535 iterations left)
Estimated time remaining for 1784630^65536+1 is 0:03:38

Successful computation progress with x87 (80-bit); switching back to SSE4.
Using SSE4 transform
Resuming 1784630^65536+1 from a checkpoint (49151 iterations left)
Estimated time remaining for 1784630^65536+1 is 0:00:29
1784630^65536+1 is complete. (409702 digits) (err = 0.4062) (time = 0:10:39) 01:36:56
01:36:56 (4812): called boinc_finish

It's even more complicated. These are two Intel AVX CPUs on the same workunit. They're not identical CPUs, however. But one's Windows, the other is Mac. Different compilers.

Some of my wus are switching to SSE4. Are we closing to the limits of AVX?

We are going really fast. :)

I'm considering 65536 to have "switched" from 64 to 80 bit CPU processing.

EDIT: Same thing for 131072 Low. 80 bit CPU for an increasing percentage of tasks.
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My lucky number is 75898⁵²⁴²⁸⁸+1

I'm considering 65536 to have "switched" from 64 to 80 bit CPU processing.

I'm considering 65536 to have "switched" from 64 to 80 bit CPU processing.

Not completely yet. I've checked runtimes for last 24 hours. On true FMA transform, runtime should be about 8 minutes. Now they're between 8-11 minutes. Most of tasks are bouncing between FMA3-AVX transforms, and only one task had full x87 processing (took more then one hour) and two or three switched in the middle (~30 minutes). But the situation may change within few hours.

It's fuzzy, so some tasks (and hosts) will switch, some will switch partway, and so forth.

If you're concerned about tasks taking hours instead of minutes, it's time to stop running n=16 and n=17 on a CPU.

OCL (n=21/22) app has a GTX970 around 35-45% slower than the Titan.

It's certainly been worthwhile doing the PRPNet double checks. So far we've found five!!! primes that were missed initially on PRPNet. Two on 32768 and three on 65536.

We're roughly halfway through the double checking on both ranges.

I can't wait to see how many primes we find once we're into new territory on those searches!

We're doing more than 45 thousand 32768 tests per day, and about 8 thousand 65536 tests per day.
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My lucky number is 75898⁵²⁴²⁸⁸+1

How many primes are still to be found?

I did some digging, finding all the GFN primes that PrimeGrid has found, and all (I think) the primes that anyone else has found for n=15 and above. Using Yves' expected primes calculator, and plugging in the total number of primes already found and the b-limits of OCL3, I came up with the following table that shows how many primes we can expect to find using OCL3.

I came up with the following table that shows how many primes we can expect to find using OCL3.

n = 19, [2; 895,000[ was a lucky range (4 primes, 1.77 expected). But this doesn't imply that [895,000; 4,194,304[ is an unlucky range and that 3.40 primes are expected in it. 5.62 primes are expected in this range.
On the other hand, n = 20, [2; 720,000[ was unlucky with no prime and 0.8 expected. But 2.16 primes are expected in [720,000; 2,965,821[, not 2.97.

What's certain is that OCL3 is going to breath new life into 18 and 19 and 20, and there should be a very good chance of finding the largest known GFN prime in either 19 or 20.

How many primes are still to be found?

I did some digging, finding all the GFN primes that PrimeGrid has found, and all (I think) the primes that anyone else has found for n=15 and above. Using Yves' expected primes calculator, and plugging in the total number of primes already found and the b-limits of OCL3, I came up with the following table that shows how many primes we can expect to find using OCL3.

n 15 16 17 18 19 20 21 22 2^n 32,768 65,536 131,072 262,144 524,288 1,048,576 2,097,152 4,194,304 PG Primes 87 29 2 6 4 0 0 0 Non-PG Primes 56 29 10 1 0 0 0 0 OCL3 limit 16,777,216 11,863,283 8,388,608 5,931,642 4,194,304 2,965,821 2,097,152 1,482,910 Expected primes 190.93 133.23 47.39 20.27 7.40 2.97 1.20 0.47 Remaining primes 47.93 75.23 35.39 13.27 3.40 2.97 1.20 0.47

The bottom line is how many more primes we can expect to find at each n if we search each to the limit of OCL3.

Of note is only can we expect to find many more primes at the lower n ranges, but that with the expanded range available with OCL3 we may also find some large primes.

Any primes found with N=32768 will be too small to be reported to the T5K list.

Any primes found with N=32768 will be too small to be reported to the T5K list.

Seeing this, it got me thinking: what's the point of moving on with GFN 15?