Re: [Boost-users] [Boost.Array] surprising performance issue

From: Andrei (andrei_keino_at_[hidden])
Date: 2007-11-27 11:21:03

I already hear  about the boost::array peformance luck. 
If you need really fast math library, you could try Blitz++ library arrays, it's perfomance is nearly as good as FORTRAN - coded program one. You may find some info about Blitz++ on the codeproject.com || codeguru.com.

Hope this helps.

Andrei

-----Original Message-----
From: KSpam <keesling_spam_at_[hidden]>
To: boost-users_at_[hidden]
Date: Tue, 27 Nov 2007 08:25:52 -0700
Subject: Re: [Boost-users] [Boost.Array] surprising performance issue

> 
> Bryan,
> 
> > I've discovered a situation where using boost::array results in a
> > 2-fold performance degradation over other array types, including C arrays,
> > tr1::array, and a simple handwritten array class.
> > While the tr1::array performs well, I was suprised to find that it pads the
> > array, so sizeof(tr1::array<3,float>) == sizeof(tr1::array<4,float>).  Is
> > that a requirement of tr1::array?
> 
> It is very strange that you see a performance difference between tr1::array 
> and boost::array.  I think that boost::array was used as a submission for 
> tr1::array (they are likely one and the same).
> 
> > Anyway, the performance problem can be seen using Intel C++ (v9.1) on the
> > Itanium platform, using '-O3' optimization.
> 
> In your build environment, ensure that you ARE NOT defining _DEBUG, and that 
> you ARE defining NDEBUG.  These flags can make a significant difference in 
> run-time performance.  Just because you are compiling with optimization flags 
> does not necessarily mean you are running the most optimized code :-)
> 
> Hope This Helps,
> Justin
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