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Date: Mon, 19 Mar 2012 10:24:08 -0400
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Subject: Re: [gentoo-user] Changing compilers
From: Michael Mol <mikemol@gmail.com>
To: gentoo-user@lists.gentoo.org
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On Mon, Mar 19, 2012 at 10:05 AM, Andrew Lowe <agl@wht.com.au> wrote:
> On 03/19/12 20:34, Mark Knecht wrote:
>> On Mon, Mar 19, 2012 at 5:32 AM, Mark Knecht <markknecht@gmail.com> wrot=
e:
>>> On Sun, Mar 18, 2012 at 10:26 PM, Andrew Lowe <agl@wht.com.au> wrote:
>>>> Hi all,
>>>> =C2=A0 =C2=A0Has anyone played around with the various "better known" =
compilers on
>>>> Gentoo? By "better known", I'm referring to gcc, Intel, llvm, pathscal=
e. My
>>>> situation is that I've just started my PhD which requires me to do Fin=
ite
>>>> Element Analysis, FEA, and Computational Fluid Dynamics, CFD, and I wa=
nt to
>>>> find the "best" compiler for the job. Before anyone says "Why bother, =
XXX
>>>> compiler is only 1 - 2% faster than gcc", in the context of the work I=
'm
>>>> doing this 1 - 2% IS important.
>>>>
>>>> What I'm looking for is any feedback people may have on ability to com=
pile
>>>> the Gentoo environment, the ability to change compilers easily, gcc-co=
nfig
>>>> or flags in make.conf, as to whether the compiler/linker can use the
>>>> libraries as compiled by gcc on a "standard" gentoo install and so on.
>>>> Obviously there is much web trawling to be done to find what other peo=
ple
>>>> are saying as well.
>>>>
>>>> Any thoughts, greatly appreciated,
>>>> =C2=A0 =C2=A0 =C2=A0 Andrew Lowe
>>>>
>>>>
>>>
>>> Think CUDA
>>>
>>> Mark
>>
>> Sorry. Meant to include this reference: <$15 on Kindle. Reads great on
>> Kindle for PC.
>>
>> http://www.amazon.com/CUDA-Example-Introduction-General-Purpose-ebook/dp=
/B003VYBOSE/ref=3Dsr_1_4?ie=3DUTF8&qid=3D1332160431&sr=3D8-4
>>
>>
>
> =C2=A0 =C2=A0 =C2=A0 =C2=A0I'm sorry but I'm doing a PhD, not creating a =
career in Academia. The
> concept of writing an FEA or CFD from scratch, with CUDA is laughable, I
> just don't have the time to learn CUDA, research the field, small
> displacement, large displacement, dynamics, material nonlinearities,
> write the code, and then most importantly benchmark it to make sure it's
> actually correct. This is all bearing in mind that I have 20+ years
> experience as a C/C++ technical software developer, including FEA and
> CFD. I'll actually be using Code Aster, an open source FEA code that
> runs under Linux.
>
> =C2=A0 =C2=A0 =C2=A0 =C2=A0Sorry if I sound narky, but compilers is the s=
ubject at hand, not how
> to write FEA code.
If you really care about a 1-2% difference, you should not be
dismissing GPGPU-accelerated code so easily! If the tools you seem to
have already settled on don't support it, you should either use
different tools, or correct the ones you're working with.
The lead Python guy had an astute observation (which I'll generalize)
the other day; for 99% of your program, it doesn't matter what
programming language you use. For the 1% where you need speed, you
should call out into the faster language.
--=20
:wq