Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!pacific.mps.ohio-state.edu!linac!midway!midway.uchicago.edu!francis From: francis@zaphod.uchicago.edu Newsgroups: comp.sys.mac.programmer Subject: Re: Prime numbers, Help Message-ID: Date: 14 Apr 91 04:37:02 GMT References: <1991Apr4.164338.329@asacsg.mh.nl> <8742@ucdavis.ucdavis.edu> <1991Apr11.020157.11756@agate.berkeley.edu> <1991Apr11.145247.16673@ux1.cso.uiuc.edu> Sender: news@midway.uchicago.edu (NewsMistress) Organization: Mathematics Department, University of Chicago Lines: 21 In-Reply-To: rolf@sparc1's message of 11 Apr 91 14: 52:47 GMT In article <1991Apr11.145247.16673@ux1.cso.uiuc.edu> rolf@sparc1 (Rolf Wilson) writes: If you only need to determine the primality up to 65,536, just include a "bitmap" of 0 and 1 to show if each number is prime. At 1 bit per number, only 8192 bytes are required. Store only the odd numbers (remember to make 2 a special case) and the storage drops to 4096 bytes. I knew a guy once (you out there, Steve?) who did this with his Apple II, using an entire floppy (as in, *all* of it--every single bit of the 140K). Said his drive was running nonstop for a day and a night. Just a tidbit from the randomizer that serves as my memory... -- /============================================================================\ | Francis Stracke | My opinions are my own. I don't steal them.| | Department of Mathematics |=============================================| | University of Chicago | Until you stalk and overrun, | | francis@zaphod.uchicago.edu | you can't devour anyone. -- Hobbes | \============================================================================/