Re: [boost] Metaprogram benchmarks

Subject: Re: [boost] Metaprogram benchmarks
From: Dave Abrahams (dave_at_[hidden])
Date: 2012-04-04 16:04:55

on Wed Apr 04 2012, Karsten Ahnert <karsten.ahnert-AT-ambrosys.de> wrote:

> On 04/03/2012 07:56 PM, Dave Abrahams wrote:
>> 
>> In order to measure the compile-time efficiency of various C++11
>> metaprogramming techniques, I'd like to put together a set of
>> benchmarks, and I wanted to discuss here what kinds of tests might be
>> appropriate.  Aleksey and I came up with some benchmarks for an appendix
>> to http://boostpro.com/mplbook/, but some of those are lost and they're
>> all getting a bit crusty.  Certainly, I have no confidence that they are
>> realistic or useful.  If anyone has ideas about this, I'd be very
>> glad to hear them.
>> 
>> Thanks in advance,
>> 
>
> What about some programs and examples from this thread
>
> http://thread.gmane.org/gmane.comp.lib.boost.devel/211140
>
> I remember that the compilation of a simple sine needed about 10 minutes
> to compile. But I am not sure if new techniques from C++11 will helf to
> increase the performance here.

Well, I happen to know that such numeric computations can be done
comparatively quickly using constexpr,
e.g. see the computation of pi in
https://github.com/dabrahams/mpl11/blob/master/standalone/constexpr_demo.cpp

I don't know enough about how the Van Wijngaarden method works to
identify a converged result, but IMO the techniques used there prove the
concept.  Note, for example, the creation and traversal of compile-time
linked datastructures using constexpr with regular pointers :-)

-- 
Dave Abrahams
BoostPro Computing
http://www.boostpro.com