[racket] 80-bit precision in Racket

On Tue, Nov 13, 2012 at 10:43 PM, Hugh Aguilar <hughaguilar96 at yahoo.com>wrote:

> > We are doing numerical integration of celestial bodies over large
> periods of time (100 years is a norm).
>
> I'm new to Scheme, so I may be totally wrong about this --- but, isn't a
> numerical program like this exactly what Scheme is *not* designed for?
>

The Supercomputer Toolkit (
http://www.hpl.hp.com/techreports/94/HPL-94-30.html ) was
designed for doing numerical integration of celestial bodies over large
periods of time.

"The Toolkit's compiler uses a novel strategy based upon partial evaluation
[7, 9]. This exploits the data-independence of typical numerical
algorithms to generate exceptionally efficient object code from source
programs that are expressed in terms of highly abstract components written
in
the Scheme dialect of Lisp [14]."

"The integrator and the force law were written as high level Scheme
programs. The accumulation of position was implemented in
quad precision (128 bits), and the required quad precision operators were
written in Scheme."

"In hindsight, the use of quad precision appears to have been overly
conservative for this
problem"

-- 
~jrm
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