Language Shootout

[Dave]

Don Clugston wrote:
> David B. Held wrote:
>> Dave wrote:
>>> Dan Wrote:
>>>
>>>> Hi guys,
>>>>
>>>> This idea will only work with Walter in on it.  : p  I was thinking 
>>>> that we might go through the various benchmarks in "the language 
>>>> shootout" and find out those items where D is significantly behind 
>>>> for any reason, and correct the performance.
>>>>
>>>> For example, against Eiffel, you see their Fasta implementation is 
>>>> 38 times faster than D's.  Why not compile the code, find out how it 
>>>> works and see why D's that much slower - and then Walter can fix the 
>>>> code?
>>>>
>>>
>>> Huh? D is a tad better on one machine and just a bit slower on the 
>>> other machine (on the Shootout). Maybe there was some sort of problem 
>>> on the site when you looked at it?
>>>
>>> http://shootout.alioth.debian.org/gp4/benchmark.php?test=fasta&lang=all
>>>
>>> http://shootout.alioth.debian.org/debian/benchmark.php?test=fasta&lang=all 
>>>
>>
>> In fact, the D version is written nicely, but the the fastest C++ 
>> version is clearly written for speed.  I'm willing to bet that D could 
>> close the gap by taking away all classes and using free functions + 
>> structs the way the C++ version does.  Anybody up for it?  Since we 
>> can't test on the shootout machine itself, improvements should be 
>> measured relative to the currently published version.
> 
> Try changing the constants in the Random class to be 'const double' 
> instead of 'const int'. Mixing ints and doubles is really slow.
> 
> Try replacing the Random class with:
> 
> double genRandom(double max)
> {
>    static double seed = 42;
>    const double IA = 3877, IC = 29573, IM = 139968;
> 
>    return max * ((seed = (seed * IA + IC) % IM) * (1.0 / IM));
> }

I tried that and get about 10% slower on a P4?

Thanks,

- Dave