[racket] translate from Racket to Common Lisp

I think it is difficult to see that those integers do not escape
fixnum range. :)

On Sun, Nov 4, 2012 at 7:42 PM, Matthias Felleisen <matthias at ccs.neu.edu> wrote:
>
> Hmph. I would expect TR to perform as fast as 'unsafe'.
>
>
> On Nov 4, 2012, at 7:40 PM, Matthew Flatt 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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>