RE: [boost] Formal Review for Interval Library beginning

From: Paul A. Bristow (boost_at_[hidden])
Date: 2002-09-03 11:41:23

I have read the documentation and a little of the code and examples,
but not run any examples.

There is a very clear need for an interval arithmetic package,
and I believe this provides what is needed.  Indeed, a very impressive
amount of thought and work and detailed testing has gone into it.

I vote immediately for acceptance.

However, I think the documentation and examples do not help those
whose mathematical knowhow is/was inadequate, obselete and/or decayed.
Like it or not, many potential users (including me) fall into this category,
and it would be a shame to deter them for want of assistance on the first
step.

I suggest that a little more detail in defining meanings, with many more
examples,
would help a lot in selling this more widely.
Even symbols like [] and the box [_] are not obvious to non-mathematicans.
The difference between std::max and min and interval max and min is not
obvious,
badly needs examples, and of usage, and perhaps should have a different
name?
The functions are rather tersely defined and examples would be very helpful.

References and/or links to math texts (if even they are 'standard' to
mathematicians)
seem an essential and very easy addition.

I would have found some more elementary examples of use helpful.
(But I was impressed by the detailed testing examples).

And an example of use with a bigint type would provide proof of
extensibility.

On a detail, I note that PI is only defined to 21 decimal digits, which
might be insufficient
for some potential uses.  Why is it not just defined to 40 decimal digits,
sufficient for any foreseable floating point hardware,
even allowing for the known need for a few extra digits - see Kahan's paper.
We should be able to assume that the compiler will convert this to
the best representation that is possible for the floating point type,
(if it doesn't then it is not compliant).
Then shouldn't + and - numeric_limits epsilon, pred and succ,
or nextafter(x, +inf) and (x,-inf) function provide the pi() interval
values?

Finally I note that there remains a need for an even more complex system
to handle the uncertainty of real physical measurements whose statistical
properties
(distribution, for example, gaussian or rectangular, degrees of freedom etc)
are known.,
and need proprgation through calculations.
This package deals with the computational 'uncertainty' and provides a
foundation
on which in future to handle what we also know about the measurement
uncertainty.

Paul

Dr Paul A Bristow, hetp Chromatography
Prizet Farmhouse, Kendal, Cumbria, LA8 8AB  UK
[phone]  Mobile [phone]
mailto:pbristow_at_[hidden]

> -----Original Message-----
> From: boost-bounces_at_[hidden]
> [mailto:boost-bounces_at_[hidden]]On Behalf Of Beman Dawes
> Sent: Saturday, August 31, 2002 1:02 PM
> To: boost_at_[hidden]
> Subject: [boost] Formal Review for Interval Library beginning
>
>
> The Formal Review period of the Interval Library begins today, August 31,
> and runs through Monday, September 9. The submission is from Hervé
> Bronnimann, Guillaume Melquiond, and Sylvain Pion, based on an initial
> version from Jens Maurer.