Perhaps the elegance of your phrase (idiom?) was not your first concern, but I would prefer
;:^:_1 'MWDhms' (,~ ":)&.> _ 4 7 24 60 60 #: <. (<:2^55) % 4*3e9 1M 0W 6D 17h 59m 59s R.E. Boss > -----Oorspronkelijk bericht----- > Van: [email protected] [mailto:[email protected]] > Namens Dan Bron > Verzonden: dinsdag 23 februari 2010 23:55 > Aan: 'General forum' > Onderwerp: Re: [Jgeneral] GB_Flip RNG seed > > Roger wrote: > > Tell that to the people who complained that the GB_FLIP > > period (_1+2^55) is not long enough. > > Mainstream personal use computers these days have 4 effective CPUs, each > clocking in at 3 Ghz. Assuming you devoted one such > machine to entirely to generating random numbers using the GB_FLIP > algorithm, and each processor could generate one random number > per cycle, then: > > ;:^:_1 'MWDhms' ,&":&.>~ _ 4 7 24 60 60 #: <. (<:2^55) % 4*3e9 > 1M 0W 6D 17h 59m 59s > > It would take over a month before algorithm cycled. Of course, this > ignores real-life concerns such as memory size, bus speeds, > cycles lost to an OS and other processes, not to mention you probably > couldn't generate a random number per cycle, and even if you > could, since each number depends on the previous, then you couldn't > parallelize the algorithm across 4 processors like this. So > add a little buffer and call it two months. > > I'd be interested in learning which applications have such appetites for > random numbers that this period is too short for them (and > do they really run models over the course of a month?). > > -Dan > > > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
