[racket] slow g^x=h mod p meet in the middle code

Well done. I would never have thought of compiling with CGC.

Neil ⊥

On 02/28/2014 11:46 AM, Matthew Flatt wrote:
> Cristian determined that Racket really was was much slower for the
> program on Windows than on other platforms, and he also noticed that
> RacketCGC was significantly faster.
>
> That information pointed me to a simple inefficiency in the way Racket
> allocated for GMP with the default collector. I've pushed a repair, and
> Matthias's version of the program (which is a little faster than the
> original) now runs about 4 times as fast on my machine (similar to the
> Java version).
>
> Fixing the bug was easy. The hard work was recognizing that something
> was wrong and in what circumstances --- so thanks to everyone for that,
> especially Cristian.
>
> At Thu, 27 Feb 2014 19:10:06 -0500, Eric Dong wrote:
>> On my computer the Java program takes 7 seconds. So you should be seeing a
>> 3x slowdown with Racket.
>>
>> You seem to see a 20x slowdown. This is very strange. How much RAM do you
>> have? Racket performs very poorly when its memory is swapped out to disk.
>>
>> To the rest of the list: is there any inefficiency with Racket on Windows
>> that could cause this massive slowdown?
>>
>>
>> On Thu, Feb 27, 2014 at 6:34 PM, Cristian Baboi
>> <cristian.baboi at gmail.com>wrote:
>>
>>>
>>>
>>> On 28 februarie 2014 01:13:46 EET, Eric Dong <yd2dong at uwaterloo.ca> wrote:
>>>
>>>> Windows shouldn't be much slower though. What CPU model do you have?
>>>> (2.0
>>>> GHz can be fast or slow depending on your CPU model)
>>>>
>>>
>>> AMD Athlon 3800+ X2
>>>
>>>
>>> Also, can you post a Python program that runs much faster? Maybe it is
>>>> only
>>>> your computer which is slow, and it would be even slower running the
>>>> Python
>>>>
>>>
>>> I attached a Java program  I tested and it ran much faster. 13 s.
>>>
>>> I cannot test python because I don't have it installed and require some
>> libraries for big number arithmetic. I don't know python.
>>>
>>>
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