Re: [boost] formal review request : mcs::units

From: Matthias Schabel (boost_at_[hidden])
Date: 2007-02-09 01:51:55

Hi Steven,

> I uploaded another version of dimension.hpp.  If there are any
> problems let me know.  I hope that these optimizations are sufficient.

I would like to publicly commend you on an excellent job of  
optimizing the core metaprogramming
code in the mcs::units library. I ran a test of the compilation time  
on unit_example_4, which is the most
extensive example, comparing my original implementation to your  
optimized one. The results are quite
impressive: averaged over four trial runs starting from a clean build  
using gcc 4.0.1 on a 2.16 GHz
MacBook Pro, I get

original dimension.hpp	: 78s compilation time
new dimension.hpp		: 8s compilation time

Time to build all examples:

original dimension.hpp	: 105s
new dimension.hpp		: 28s

Almost 10x and 4x, respectively = very nice work. This removes one of  
the major objections raised to previous
versions of this library and makes using it relatively painless.  
Thanks for your input. I've checked the output
of the example programs, and everything appears to work as  
previously, so I have committed the new code
(v0.6.0) and posted a new version in the Vault which I heartily  
recommend to interested parties.

Matthias