Re: [boost] [Review] Review of the Accumulators library begins today, Jan 29

From: Paul A Bristow (pbristow_at_[hidden])
Date: 2007-02-05 09:38:21

>-----Original Message-----
>From: boost-bounces_at_[hidden] 
>[mailto:boost-bounces_at_[hidden]] On Behalf Of John Phillips
>Sent: 29 January 2007 14:15
>To: boost_at_[hidden]
>Subject: [boost] [Review] Review of the Accumulators library 
>begins today,Jan 29
>
>The formal review of the Boost.Accumulators library, submitted by Eric 
>Neibler begins today and ends on Wednesday, February 7. The library is 
>available from
>
>http://boost-consulting.com/vault/index.php?directory=Math%20-%>20Numerics
>
>Here are some questions you might want to answer in your review:
>	. 	What is your evaluation of the design?

It looks to be a rather useful framework for handling incrementally arriving data.

It may also prove convenient where the data could just as well be handling in a plain array, vector or similar format.
(But what about compared to using Boost circular buffer?)

>	. 	What is your evaluation of the implementation?

I can see why it is done this way and believe it is sound, but at a price of looking pretty intimidating, though probably easy
enough in practice.

I worry slightly about compile time and perhaps run time costs, but worth it.

Basic testing looks fine.

It would be a mistake now to focus too much on the detailed implementation/accuracy of actual functions - it is the framework that
matters now.

However there is a danger, as with all statistical calculations, of confusing data with information. 

For example, hardly any useful *information* on skewness or kurtosis is likely to emerge from a handful of values, even if
mathematically accurate.

But the framework is templated so that one can envisage a floating-point type that adds uncertainty estimates as well as central
values.
So we would know that the skew is -0.5 (but + or - a very lot).

>	. 	What is your evaluation of the documentation?

Looks good, and has a good structure - but I haven't used it 'in anger' - when things are always missing/unclear.

>	. 	What is your evaluation of the potential usefulness of the  library?

I am uncertain if it will meet a niche market - real-time systems seem the obvious applications, and yet I fear that those working
on these small machines  - the 'toaster market ;-) may take fright at the apparent complexity, especially if the chip lacks built-in
floating point (but has a UDFPT).

>	. 	Did you try to use the library? 

Not much - some examples worked OK MSVC 8.0.

>	. 	How much effort did you put into your evaluation?

Quickish read of docs, and some code and ran a few examples.

>	. 	Are you knowledgeable about the problem domain?

Not especially.

>And finally, every review should answer this question:
>	. 	Do you think the library should be accepted as a Boost library?  

Yes - definitely.

Paul

---
Paul A Bristow
Prizet Farmhouse, Kendal, Cumbria UK LA8 8AB
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pbristow_at_[hidden]