factor

Author	SHA1	Message	Date
John Benediktsson	ad71f79be3	math.primes: speedup sieve.	2014-12-04 10:11:32 -08:00
John Benediktsson	eaa19eb36f	math.primes.erato: minor performance improvements.	2012-10-23 10:49:45 -07:00
John Benediktsson	dd2a5729a7	math.primes.erato: bit faster by inlining.	2012-08-23 09:35:09 -07:00
Rupert Swarbrick	cd28c7a219	math.primes.erato: Fix off-by-one error The sieve bit vector deals with numbers in chunks of 30. Therefore, the number 90 (say) is the 91st 'element' of the vector. Each byte deals with some range {0,1,...,29}+30n so to have the number 90, you need four bytes. Rather pleasingly, I bumped into this bug and it reduced to the incantation: 2010 2010 sieve marked-prime?	2010-11-02 17:34:24 +01:00
Doug Coleman	4a3d63e00a	use if-zero in a few more places	2009-08-11 18:15:53 -05:00
Samuel Tardieu	41d804ddbd	Pack primes numbers by slices of 30 In any given 30 successive integers greater than 5, there are at most 8 prime numbers. Use this to tightly pack the result of the Eratostene sieve. This lets us store more prime numbers than before in less space.	2009-06-24 13:15:12 +02:00
Samuel Tardieu	594bd3aee8	Move math.primes from extra to basis	2009-01-07 21:12:48 +01:00