Re: [boost] [Accumulators] is there an updated version?

From: Eric Niebler (eric_at_[hidden])
Date: 2008-01-02 12:43:45

Sorry for the delay, the holidays were a busy time.

Jamie Allsop wrote:
> I recently had a need for some simple statistical analysis of 
> performance data and thought rather than sit down and write my own 
> functions for mean, variance etc. I'd take the time to learn and use the 
> Accumulators library that was accepted into boost on February the 19th 
> of this year,
> <http://lists.boost.org/boost-announce/2007/02/0114.php>
> 
> The only version I could find was that in the vault,
> <http://www.boost-consulting.com/vault/index.php?action=downloadfile&filename=accumulators.zip&directory=Math%20-%20Numerics&>
> 
> This appears to have been updated last on 21.09.2007 03:32.
> 
> The first thing I am wondering is why this library is not in TRUNK now 
> that it is a part of boost?

The library wasn't ready for 1.35, so I never put it in trunk. Now that 
we've branched for release, I can put accumulators in trunk and continue 
development there.

> Secondly I thought I'd comment briefly on something that I noticed came 
> up during review but has (as yet) not been addressed in the vault 
> version. I too assumed that using boost::accumulators::tag::variance 
> would return a useful value for variance, unfortunately it returned (in 
> my case) what appeared to be an erroneous negative value. The 
> 'immediate_' form worked ok.
> 
> My comment would be that after reading the review there was some debate 
> about providing a naive implementation. My thought after spending time 
> reading the reviews and browsing the code to try to figure out what was 
> happening was that, if I wanted a naive implementation, I could provide 
> that easily myself. However I turned to the library to
> a) save me writing and maintaining the code, and
> b) to enjoy a well thought out implementation by a domain knowledgeable 
> implementor.
> 
> I therefore think that the natural choices should be accurate 
> implementations. If I know enough about my data to realise I can get 
> away with a naive implementation that sacrifices accuracy (perhaps for 
> performance reasons) then I can select one purposefully.

Fair enough. Thanks for taking the time to give your feedback. I haven't 
yet addressed this issue, but I tend to agree with you and will give 
this some serious consideration.

> My first experience with the accumulators library was a mixed bag, but I 
> have not used it enough to really form too many opinions on it. I 
> suppose when I initially looked at it I thought I would have access to 
> statistical algorithms that I could apply to my data, but in fact it 
> works differently than that (and I am sure there was a good reason for 
> that approach). I'll have to revisit the doc to see if I can find 
> understand the motivation better. It works well as it is mind you.
> 
> Beyond that the library appears useful and I look forward to making more 
> use of it.
> 
> I'd be very interested in seeing a newer version of the library that 
> addresses the many points highlighted during the review or at least know 
> that the library is currently being tidied up and will make into a boost 
> release soon :)

Much of the feedback from the review has already been incorporated into 
the version in the file vault. It's getting there, but slowly. I have a 
day job and libraries shipping in 1.35 that needed maintenance, and 
those took precedence. Sorry for the delay ... the library *will* make 
its appearance in trunk soon.

-- 
Eric Niebler
Boost Consulting
www.boost-consulting.com