Re: [Boost-users] [boost] C++ Performance

From: Mike Marchywka (marchywka_at_[hidden])
Date: 2007-11-20 14:39:09

>> Im a quite new boost user and I wonder, why C++ Program is so slow.

Check out some of the literature on your platform- if it is ia-32, see the
links I posted earlier or go to Intel site. Don't assume that because
you have a math program that you are limited by some "math thing."
On larger data sets it is almost impossible to get a cache ignorant implementation
of anything to run fast. And, don't rule out file IO or some other limitations.
I'm probably paranoid about this because on cygwin it has been a big problem
but time the suspect code before assuming it to be the time sink.
Things like exceptions can be a big problem- if you have an ill conditioned
or pathological problem and let the FPU throw 10 billion exceptions, it will
be slow- it could be your other program checks for stuff like this.

Mike Marchywka
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> From: maikbeckmann_at_[hidden]
> To: boost-users_at_[hidden]
> Date: Tue, 20 Nov 2007 20:07:42 +0100
> Subject: Re: [Boost-users] [boost] C++ Performance
>
> Forwarded to boost-users...
>
> Am Dienstag 20 November 2007 16:24:42 schrieb nisha kannookadan:
>> Hi everybody
>>
>> Im a quite new boost user and I wonder, why C++ Program is so slow.
>>
>> I wrote a program, and I have the same program in Matlab,
>> I expected that my C++ version is much faster, but its not.
>>
>> I use matrices, vectors, matrix- and vector proxies. Do some
>> solving and compute calculations with prod, element_div, etc..
>>
>> Is boost in general slower than matlab, should I use something
>> else?
>>
>> Id be real happy about any help.
>>
>> Regards
>> Nisha K
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