Re: How fast is LuaJIT supposed to be?
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- Subject: Re: How fast is LuaJIT supposed to be?
- From: "Joseph Manning" <manning@...>
- Date: 2011年1月21日 17:59:33 +0000
On 2011-Jan-21 (Fri) at 18:08 (+0100), Valerio Schiavoni wrote:
>> hello Joseph
>>
>> On Fri, Jan 21, 2011 at 12:04 PM, Joseph Manning <manning@cs.ucc.ie> wrote:
>>
>> >>> for kk = k*2, max, k do
>>
>> > faster : for kk = k*k, max, k do
>>
>> does it mean k*k is faster than k*2 ?
No, sorry, I guess my initial message may have been too terse.
I simply meant to convey that the overall Sieve of Eratosthenes program
will be faster if the above loop starts at k*k rather than at k*2 ,
since it will have fewer iterations to go through.
And it's quite safe to start with k*k as being the first multiple of k
to be eliminated, since smaller multiples of the form k*i ( i < k )
will already have been eliminated, since they are multiples of i.
Perhaps in the context of benchmarking, the whole point is moot anyway,
as a slower algorithm can serve as a better benchmark than a faster one,
in the sense of better highlighting the difference in run-time speed
between different systems.
-- Joseph
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Joseph Manning / Computer Science / UCC Cork Ireland / manning@cs.ucc.ie
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