1 May
2010
1 May
'10
11:26 p.m.
On May 1, 2010 04:19:22 pm you wrote:
On Sat, May 1, 2010 at 11:57 AM, Tim E. Real
<termtech(a)rogers.com> wrote:
Thanks for the comments. That's really smart of Java!
Beautiful.
I guess they don't fool around in an app like Mathematica, either.
I'm familiar with Scheme via the Geda suite, but less so with Lisp.
The last time I dealt with BCD was in the great Borland C++ Builder.
At the time version 4 had minimal support for it, but in the end
I had to write my own classes for it, when I had to switch my entire
DB app from 'NUMBER' to 'BCD' fields. Ugh... Yeah, slow and a PITA.
I've always wondered why they don't make a fixed-point co-processor...
Thanks. Tim.
Can I get some comments on an issue nagging me
for years:
Maybe I never learned some golden rule about floating point,
please correct me if I'm ignorant of some crucial technique or fact
which would help: ...
Arbitrary precision arithmetic will take care of all these problems. At a
great cost to performance:
http://en.wikipedia.org/wiki/Arbitrary-precision_arithmetic .
It's part of the Java Language:
http://java.sun.com/j2se/1.4.2/docs/api/java/math/package-summary.html
Provides classes for performing arbitrary-precision integer arithmetic
(BigInteger) and arbitrary-precision decimal
arithmetic (BigDecimal).
BigInteger is analogous to Java's primitive integer types except that it
provides arbitrary precision, hence operations on BigIntegers do not
overflow or lose precision. In addition to standard arithmetic
operations, BigInteger provides modular arithmetic, GCD calculation,
primality testing, prime generation, bit manipulation, and a few other
miscellaneous operations. BigDecimal provides arbitrary-precision signed
decimal numbers suitable for currency calculations and the like.
BigDecimal gives the user complete control over rounding behavior,
allowing the user to choose from a comprehensive set of eight rounding
modes.
Arbitrary precision math has been part of the Lisp/Scheme world for a long
time; it's also in the mainstream via mathematica:
http://groups.google.com/group/comp.soft-sys.math.mathematica/topics?pli=1
-- Niels
http://nielsmayer.com