Newsgroups: comp.lang.lisp
Path: cantaloupe.srv.cs.cmu.edu!das-news.harvard.edu!news2.near.net!MathWorks.Com!yeshua.marcam.com!usc!elroy.jpl.nasa.gov!lll-winken.llnl.gov!fnnews.fnal.gov!gw1.att.com!nntpa!nntpa.cb.att.com!lgm
From: lgm@polaris.ih.att.com (Lawrence G. Mayka)
Subject: Re: C is faster than lisp (lisp vs c++ / Rick Graham...)
In-Reply-To: tmb@arolla.idiap.ch's message of 02 Sep 1994 00:31:08 GMT
Message-ID: <LGM.94Sep4131854@polaris.ih.att.com>
Sender: news@nntpa.cb.att.com (Netnews Administration)
Nntp-Posting-Host: polaris.ih.att.com
Organization: AT&T Bell Laboratories, Naperville, Illinois, USA
References: <CuzxyG.6v2@triple-i.com> <TMB.94Aug24222912@arolla.idiap.ch>
	<Cv5DsM.9q8@cogsci.ed.ac.uk> <DAVIS.94Sep1110221@passy.ilog.fr>
	<345du6$g4h@cantaloupe.srv.cs.cmu.edu>
	<TMB.94Sep2023108@arolla.idiap.ch>
Date: Sun, 4 Sep 1994 18:18:54 GMT
Lines: 21

In article <TMB.94Sep2023108@arolla.idiap.ch> tmb@arolla.idiap.ch (Thomas M. Breuel) writes:

   This "frivolous consing" is absolutely unacceptable in numerical
   code.  Even if collecting the floating point garbage were completely
   free, just the cost of allocating the values and dereferencing them is
   often much too expensive.  And, in fact, even systems with excellent
   generational GC become very slow for numerical code whenever there is
   any consing going on in the numerical code.

I've sometimes wondered: Does floating-point numerical code, of the
kind you describe, typically require IEEE precision (double or
single)?  Or can such code often make do with, say, the same 7 bits of
exponent as IEEE single-precision but only 19 bits of significand
(FLOAT-DIGITS) instead of 24?  My real question is, How often can a
cons-less SHORT-FLOAT meet this need for fast floating-point numerics?
--
        Lawrence G. Mayka
        AT&T Bell Laboratories
        lgm@ieain.att.com

Standard disclaimer.
