[math-fun] Hashlife (Was: Re: compressed bitmaps of the primes?)
I recall someone telling me about your compressed Life work back in the 1980's (??), and I thought it was extremely cool, but I haven't kept up with it.
Do you have a recent link?
Just try http://en.wikipedia.org/wiki/Hashlife . I think Elsevier still has the 1984 Physica D article paywalled. I scanned the seven separate pages as http://gosper.org/physicad0.png .. http://gosper.org/physicad6.png, (didn't somebody "staple" these?), but Tom Rokicki (et al)'s Golly<http://golly.sourceforge.net/>has exceeded my wildest expectations (and blew away Conway when I showed him).
BTW, with the advent of the "holographic universe" (wherein the details of the physics within a volume are encoded in the surface of that volume), is there a "holographic Life" ?
Dunno. Seems unlikely, due to irreversibility.
At 05:04 AM 5/24/2012, you wrote:
Also compare the growth over time of Golly's memory and save-size running Hickerson's primer, 1st quadrant of Life > Miscellaneous > four primers.
(Enumerates the primes, starting with ~ 3000 dots.)
--rwg
Bill Gosper's original test pattern was a puffer train. For those who have Golly, the initial pattern is: x = 19, y = 10, rule = B3/S23 b3o11b3o$bo2bo10bo2bo$bo6b3o4bo$bo5bo2bo4bo$2bobo2bo3bo4bobo$6b2o2bobo $8bo$9b2obo$9b3o$9b3o! Golly's implementation of Hashlife is so fast that it can run this pattern to 10^308 generations in less than 30 seconds (and using about 180 megabytes of memory) on my 3.2-GHz Intel Core i7. It's hard to time this simply because I can't get the "+" key to auto-repeat fast enough. Beyond 10^308, the generation count displays as "inf" because it overflows in the conversion to floating-point in the status display routine. (I have fixed this, and I need to send the patches to the other Golly folks). By comparison, in his 1984 paper Bill reported that "an early model Symbolics 3600" (a LISP Machine) had run Hashlife "several million steps, at a rate which doubled every two or three minutes" (once the initial non-periodic part of the exhaust trail had been fully computed). Golly does 1024 doublings in less than 30 seconds. - Robert On 5/24/12, Bill Gosper <billgosper@gmail.com> wrote:
Just try http://en.wikipedia.org/wiki/Hashlife . I think Elsevier still has the 1984 Physica D article paywalled. I scanned the seven separate pages as http://gosper.org/physicad0.png .. http://gosper.org/physicad6.png, (didn't somebody "staple" these?), but Tom Rokicki (et al)'s Golly<http://golly.sourceforge.net/>has exceeded my wildest expectations (and blew away Conway when I showed him).
-- Robert Munafo -- mrob.com Follow me at: gplus.to/mrob - fb.com/mrob27 - twitter.com/mrob_27 - mrob27.wordpress.com - youtube.com/user/mrob143 - rilybot.blogspot.com
participants (2)
-
Bill Gosper -
Robert Munafo