Re: [boost] Is there interest in e_float:Multiple-precisionfloatand special functions?

Subject: Re: [boost] Is there interest in e_float:Multiple-precisionfloatand special functions?
From: Christopher Kormanyos (e_float_at_[hidden])
Date: 2011-06-23 16:45:11

Jeff,

The original e_float publication in the ACM included a wide variety of the special functions of pure and applied mathematics
extended to large parameter ranges. When preparing this original research work, I restricted the digit range to 300 in order to
guarantee full precision of all special function calculations within known digit and parameter ranges.

In the future, it will be possible to extend e_float's digit range. In fact, the digit range can be extended any time when
using e_float with its GMP and MPFR back ends. Simple mathematics like add, sub, mul, div, sqrt, etc. work for
GMP and MPFR in very high digit ranges. However, constants like pi, log(2), Euler's gamma, etc. as well as
e_float's special functions are not yet designed for these regions and not tested therein.

Also be aware that my portable big-number back-end included in e_float (called EFX) only includes order-N^2 multiplication.
As such it can not be extended beyond several hundred digits. I can add Karatsuba and FFT multiplication to the EFX version
at a later time, as I do have these methods in other programs.

With e_float, we are making a modest first step in big-number floats for boost at this time. We need to concentrate on the
architecture and design of the program and the proper semantics of the floats. Digit extension is of secondary concern right now.


Sincerely, Chris.



________________________________
From: "Jeffrey Lee Hellrung, Jr." <jeffrey.hellrung_at_[hidden]>
To: boost_at_[hidden]
Sent: Thursday, June 23, 2011 8:23 PM
Subject: Re: [boost] Is there interest in e_float:Multiple-precisionfloatand special functions?

On Thu, Jun 23, 2011 at 8:33 AM, Christopher Kormanyos <e_float_at_[hidden]>wrote:
[...]

> Remember, e_float in its present form only goes up to 300 digits.

[...]

I'm curious, what are the reasons for this limitation?  I may have missed
this in previous discussion...

- Jeff
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