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Subject: Re: [boost] Is there interest in e_float: Multiple-precision float and special functions?
From: John Maddock (boost.regex_at_[hidden])
Date: 2011-06-02 05:01:24

>> Is there interest in my e_float library for potential inclusion in boost?
>> e_float is a portable C++ system for multiple-precision floating-point
>> calculations and
>> calculations of special functions.
> What is multiple precision floating point and how does this differ from
> float, double, or long double ?

>From memory I believe there are two key differences:

1) It performs calculations in base 10 not base 2
2) It performs calculations at 100 decimal digit precision and with a
greatly expanded exponent range compared to say [long] double.

There is tentative support for use of e_float in current Boost.Math trunk
(via boost/math/bindings/e_float.hpp), which actually proved to be a very
useful test of our code as this is the first time it's been exposed to a
real-number type that's quite so obviously base 10 as this one.

Some more general comments:

* It obviously would need quite a lot of "Boostification" before becoming a
formal submission.
* There are some (mostly interface) design choices that our perhaps
questionable, but which no doubt can be worked out.
* There *may* be a license issue, as ACM claim copyright over all
submissions to their journal (including code). I gather that ACM may be
amenable to derivative works being published under a different / more
liberal license, but that would have to be worked out formally at some point
I guess.

HTH, John.

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