Exponential operator

[Jimbob]

"Andrei Alexandrescu" <SeeWebsiteForEmail at erdani.org> wrote in message 
news:4A7C5313.10105 at erdani.org...
> Jimbob wrote:
>> "bearophile" <bearophileHUGS at lycos.com> wrote in message 
>> news:h5h3uf$23sg$1 at digitalmars.com...
>>> Lars T. Kyllingstad:
>>>> He also proposed that the overload be called opPower.
>>> I want to add to two small things to that post of mine:
>>> http://www.digitalmars.com/webnews/newsgroups.php?art_group=digitalmars.D&article_id=95123
>>>
>>> The name opPow() may be good enough instead of opPower().
>>>
>>> And A^^3 may be faster than A*A*A when A isn't a simple number, so 
>>> always replacing the
>>> power with mults may be bad.
>>
>> It wont be on x86. Multiplication has a latency of around 4 cycles 
>> whether int or float, so x*x*x will clock around 12 cycles.
>
> Yeah, but what's the throughput? With multiple ALUs you can get several 
> multiplications fast, even though getting the first one incurs a latency.

In this case you incur the latency of every mul because each one needs the 
result of the previous mul before it can start. Thats the main reason 
trancendentals take so long to compute, cause they have large dependancy 
chains which make it difficult, if not imposible for any of it to be done in 
parallel.