[racket] translate from Racket to Common Lisp

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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