[racket] translate from Racket to Common Lisp

Nice! Thanks.

Robby

On Sun, Nov 4, 2012 at 6:40 PM, Matthew Flatt <mflatt at cs.utah.edu> wrote:
> 2668 msecs when I declare `cycle-length' as `(Integer -> Integer)' and
> change `(even? n)' to `else', or 2809 msecs if I add `[else 0]' instead
> of changing `(even? n)'.
>
> At Sun, 4 Nov 2012 18:30:21 -0600, Robby Findler wrote:
>> And just to complete the list, how does the TR version fare?
>>
>> Robby
>>
>> On Sun, Nov 4, 2012 at 6:26 PM, Matthew Flatt <mflatt at cs.utah.edu> wrote:
>> > Thanks!
>> >
>> > Sometimes, a x3 difference means that we're missing a straightforward
>> > opportunity in performance, and that was the case here. The Racket
>> > program spent most of its time in generic `/' by pessimistically
>> > expecting a non-integer result.
>> >
>> > I've adjusted the JIT to optimistically compute and check a fixnum
>> > result for a division of fixnums, and then the example runs about four
>> > times as fast on my machine:
>> >
>> >  Old Racket:                12589 msec
>> >  New Racket:                 3850 msec
>> >  Racket with `quotient':     3851 msec  [old or new is the same]
>> >  SBCL:                       5553 msec
>> >  SBCL, unsafe fixnum:        2692 msec
>> >  New Racket, in module:      2823 msec
>> >  Racket, unsafe fixnum:      2405 msec  [uses `fxquotient']
>> >
>> > At Sun, 4 Nov 2012 15:54:51 +0000 (UTC), daniel rupistraliz wrote:
>> >>
>> >>
>> >>  racket:
>> >> Welcome to Racket v5.2.1.
>> >> > (define (cycle-length n)
>> >>     (cond
>> >>       [(= n 1)
>> >>        1]
>> >>       [(odd? n)
>> >>        (add1 (cycle-length (add1 (* 3 n))))]
>> >>       [(even? n)
>> >>        (add1 (cycle-length (/ n 2)))]))
>> >>
>> >> (time (for ([i (in-range 1 1000000)])
>> >>           (cycle-length i)))
>> >> >
>> >> cpu time: 15016 real time: 15018 gc time: 0
>> >>
>> >> sbcl:
>> >>
>> >> (defun cycle-length(n)
>> >>  (cond ((= n 1) 1)
>> >>        ((oddp n) (1+ (cycle-length (1+ (* 3 n)))))
>> >>        ((evenp n) (1+ (cycle-length (/ n 2))))))
>> >>
>> >>
>> >> * (time (loop for i from 1 to 1000000 do (cycle-length i)))
>> >>
>> >> Evaluation took:
>> >>   6.192 seconds of real time
>> >>   6.192387 seconds of total run time (6.192387 user, 0.000000 system)
>> >>   100.00% CPU
>> >>   14,496,643,427 processor cycles
>> >>   0 bytes consed
>> >>
>> >>
>> >> With optimizations:
>> >>
>> >> (defun cycle-length(n)
>> >>   (declare (fixnum n)
>> >>          (ftype (function (fixnum) fixnum) cycle-length)
>> >>          (optimize (speed 3) (safety 0) (compilation-speed 0)))
>> >>   (cond ((= n 1) 1)
>> >>       ((oddp n) (the fixnum (1+ (cycle-length
>> >>                                  (the fixnum (1+ (the fixnum (* 3 n))))))))
>> >>       ((evenp n) (cycle-length (the fixnum (/ n 2))))))
>> >>
>> >> CL-USER> (time (loop for i from 1 to (expt 10 6) do (cycle-length i)))
>> >> Evaluation took:
>> >>   3.515 seconds of real time
>> >>   3.524220 seconds of total run time (3.524220 user, 0.000000 system)
>> >>   100.26% CPU
>> >>   8,228,949,701 processor cycles
>> >>   33,008 bytes consed
>> >>
>> >> So racket = 15 seconds
>> >>     sbcl  =  6 seconds
>> >> sbcl optimized = 3.5 seconds.
>> >>
>> >>
>> >> ____________________
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>> >>   http://lists.racket-lang.org/users
>> > ____________________
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