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Message boards : General discussion : Pardon my ignorance

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TheCruelLogician
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Joined: 24 May 18
Posts: 131
ID: 1019105
Credit: 101,528,316
RAC: 1
Found 1 prime in the 2019 Tour de Primes321 LLR Bronze: Earned 10,000 credits (15,725)Cullen LLR Bronze: Earned 10,000 credits (34,191)ESP LLR Amethyst: Earned 1,000,000 credits (1,069,462)Generalized Cullen/Woodall LLR Gold: Earned 500,000 credits (651,908)PPS LLR Jade: Earned 10,000,000 credits (10,741,346)PSP LLR Bronze: Earned 10,000 credits (25,763)SoB LLR Amethyst: Earned 1,000,000 credits (1,529,599)SR5 LLR Silver: Earned 100,000 credits (278,040)SGS LLR Amethyst: Earned 1,000,000 credits (1,010,691)TRP LLR Gold: Earned 500,000 credits (565,318)Woodall LLR Bronze: Earned 10,000 credits (18,231)321 Sieve (suspended) Silver: Earned 100,000 credits (128,076)Generalized Cullen/Woodall Sieve (suspended) Ruby: Earned 2,000,000 credits (2,366,124)PPS Sieve Emerald: Earned 50,000,000 credits (57,620,503)AP 26/27 Jade: Earned 10,000,000 credits (10,196,446)WW Amethyst: Earned 1,000,000 credits (1,940,000)GFN Jade: Earned 10,000,000 credits (13,336,891)
Message 122999 - Posted: 29 Nov 2018 | 1:02:30 UTC

In reference to the sieve subprojects, what is a factor? I know this is a pretty elementary question, but my background is in the liberal arts / humanities (BA History / Political Science, Philosophy minor) and the only college level mathematics I took was MAT 101 (Algebra) and STA 101 (Basic Statistics). Obviously I know what factorization is and I know what a prime factor is, I'm just wondering if that is what is being referred to, or if I need a math refresher.
____________


Profile Rafael
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Joined: 22 Oct 14
Posts: 899
ID: 370496
Credit: 377,743,676
RAC: 122,432
321 LLR Turquoise: Earned 5,000,000 credits (8,236,942)Cullen LLR Turquoise: Earned 5,000,000 credits (8,028,695)ESP LLR Turquoise: Earned 5,000,000 credits (8,120,467)Generalized Cullen/Woodall LLR Turquoise: Earned 5,000,000 credits (8,011,297)PPS LLR Turquoise: Earned 5,000,000 credits (8,008,287)PSP LLR Turquoise: Earned 5,000,000 credits (8,346,305)SoB LLR Turquoise: Earned 5,000,000 credits (9,310,410)SR5 LLR Turquoise: Earned 5,000,000 credits (7,539,837)SGS LLR Turquoise: Earned 5,000,000 credits (8,631,663)TRP LLR Turquoise: Earned 5,000,000 credits (8,751,781)Woodall LLR Turquoise: Earned 5,000,000 credits (9,166,095)321 Sieve (suspended) Jade: Earned 10,000,000 credits (10,033,828)Generalized Cullen/Woodall Sieve (suspended) Jade: Earned 10,000,000 credits (10,037,204)PPS Sieve Jade: Earned 10,000,000 credits (10,305,147)Sierpinski (ESP/PSP/SoB) Sieve (suspended) Ruby: Earned 2,000,000 credits (2,000,053)TRP Sieve (suspended) Ruby: Earned 2,000,000 credits (2,030,160)AP 26/27 Jade: Earned 10,000,000 credits (12,468,612)WW Sapphire: Earned 20,000,000 credits (33,792,000)GFN Sapphire: Earned 20,000,000 credits (34,162,892)PSA Double Bronze: Earned 100,000,000 credits (170,761,999)
Message 123003 - Posted: 29 Nov 2018 | 2:21:21 UTC - in response to Message 122999.

In reference to the sieve subprojects, what is a factor? I know this is a pretty elementary question, but my background is in the liberal arts / humanities (BA History / Political Science, Philosophy minor) and the only college level mathematics I took was MAT 101 (Algebra) and STA 101 (Basic Statistics). Obviously I know what factorization is and I know what a prime factor is, I'm just wondering if that is what is being referred to, or if I need a math refresher.

When the sieves find "a factor", it means they found a small number that perfectly divides a big one. So by definition, if the big guy is divisible, it is not a prime, and therefore we don't need to waste time testing for primality, for we already know it is composite. The thing with the sieves is that, up to a point, it's faster (and early on, MUCH faster) to find factors and remove potential candidates rather than test said candidates for primality, so we do that to save time.

TheCruelLogician
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Joined: 24 May 18
Posts: 131
ID: 1019105
Credit: 101,528,316
RAC: 1
Found 1 prime in the 2019 Tour de Primes321 LLR Bronze: Earned 10,000 credits (15,725)Cullen LLR Bronze: Earned 10,000 credits (34,191)ESP LLR Amethyst: Earned 1,000,000 credits (1,069,462)Generalized Cullen/Woodall LLR Gold: Earned 500,000 credits (651,908)PPS LLR Jade: Earned 10,000,000 credits (10,741,346)PSP LLR Bronze: Earned 10,000 credits (25,763)SoB LLR Amethyst: Earned 1,000,000 credits (1,529,599)SR5 LLR Silver: Earned 100,000 credits (278,040)SGS LLR Amethyst: Earned 1,000,000 credits (1,010,691)TRP LLR Gold: Earned 500,000 credits (565,318)Woodall LLR Bronze: Earned 10,000 credits (18,231)321 Sieve (suspended) Silver: Earned 100,000 credits (128,076)Generalized Cullen/Woodall Sieve (suspended) Ruby: Earned 2,000,000 credits (2,366,124)PPS Sieve Emerald: Earned 50,000,000 credits (57,620,503)AP 26/27 Jade: Earned 10,000,000 credits (10,196,446)WW Amethyst: Earned 1,000,000 credits (1,940,000)GFN Jade: Earned 10,000,000 credits (13,336,891)
Message 123004 - Posted: 29 Nov 2018 | 2:39:42 UTC - in response to Message 123003.

Ok, thanks.
____________


JimBProject donor
Honorary cruncher
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Joined: 4 Aug 11
Posts: 916
ID: 107307
Credit: 974,532,191
RAC: 0
Discovered 1 mega prime321 LLR Ruby: Earned 2,000,000 credits (2,726,625)Cullen LLR Turquoise: Earned 5,000,000 credits (5,031,868)ESP LLR Turquoise: Earned 5,000,000 credits (5,064,082)Generalized Cullen/Woodall LLR Turquoise: Earned 5,000,000 credits (5,038,750)PPS LLR Turquoise: Earned 5,000,000 credits (5,000,461)PSP LLR Turquoise: Earned 5,000,000 credits (7,674,374)SoB LLR Sapphire: Earned 20,000,000 credits (42,604,648)SR5 LLR Jade: Earned 10,000,000 credits (11,829,173)SGS LLR Ruby: Earned 2,000,000 credits (2,413,082)TRP LLR Ruby: Earned 2,000,000 credits (2,291,092)Woodall LLR Turquoise: Earned 5,000,000 credits (5,046,412)321 Sieve (suspended) Jade: Earned 10,000,000 credits (10,057,614)Cullen/Woodall Sieve (suspended) Ruby: Earned 2,000,000 credits (4,002,919)Generalized Cullen/Woodall Sieve (suspended) Sapphire: Earned 20,000,000 credits (20,005,451)PPS Sieve Emerald: Earned 50,000,000 credits (52,042,965)Sierpinski (ESP/PSP/SoB) Sieve (suspended) Ruby: Earned 2,000,000 credits (2,341,676)TRP Sieve (suspended) Ruby: Earned 2,000,000 credits (2,070,804)AP 26/27 Jade: Earned 10,000,000 credits (10,742,251)GFN Emerald: Earned 50,000,000 credits (50,000,251)PSA Double Gold: Earned 500,000,000 credits (728,547,693)
Message 123011 - Posted: 29 Nov 2018 | 12:12:38 UTC
Last modified: 29 Nov 2018 | 12:16:25 UTC

For example, on the very earliest sieving about one third of the candidates are divisible by 3 and are removed. Somewhat less than 1/5 are divisible by 5 (because some of those were divisible by 3 and are already gone). As the factors get larger, fewer candidates are removed. For PPS sieving, the factors have reached 415,823,934,000,000,000 (but only primes are tested as being factors). We keep sieving until it's faster to remove candidates by individually testing them.

Message boards : General discussion : Pardon my ignorance

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