On Sat, Mar 08, 2014 at 11:10:20AM -0700, Matthew Flatt wrote: > At Sat, 08 Mar 2014 12:33:42 -0500, "David T. Pierson" wrote: > > cpu time: 220 real time: 220 gc time: 0 > > cpu time: 112 real time: 112 gc time: 0 > > cpu time: 60 real time: 58 gc time: 0 > > cpu time: 28 real time: 29 gc time: 0 > > cpu time: 16 real time: 15 gc time: 0 > > #t > > > > Why does the time decrease gradually, rather than the 2nd and subsequent > > times being roughly equivalent? > > When `list?` explores N pairs to determine whether its argument is a > list, it sets a bit once after N/2 pairs. That choice avoids the cost > of setting bits everywhere while providing amortized constant time for
Ah, that makes sense. And now that I look closely, I see that the time was decreasing by about half each time. Thanks. David ____________________ Racket Users list: http://lists.racket-lang.org/users
