NetNews Usenet Archive 1992 #30/NN_1992_30.iso/spool/sci/math/numanal/3549

Internet Message Format | 1992-12-11 | 1.9 KB

Path: sparky!uunet!haven.umd.edu!darwin.sura.net!wupost!usc!news.service.uci.edu!pollux.acs.uci.edu!frederik
From: [e-mail] (M. Donald Frederick)
Subject: Re: Request - Fast Exp/Log C routines
Nntp-Posting-Host: pollux.acs.uci.edu
Message-ID: <[e-mail]>
Newsgroups: sci.math.num-analysis
Reply-To: [e-mail] (M. Donald Frederick)
Organization: University of California, Irvine
Keywords: exp, log, fast, C
Lines: 28
References: <[e-mail]>
Date: 11 Dec 92 22:49:22 GMT

In article <[e-mail]>, [e-mail] (Peter K. Campbell) writes:
|> Hello out there.  We have a C program here which the profiler tells us
|> is making extensive use of exp & log functions.  Seeing as it takes
|> several days to run on a Sun Sparcstation & several hours on a Cray
|> Y-MP, we are looking for a quicker implementation of the general
|> exp/log algorithm than cc or gcc provides.
|>
|> So, would anyone out there know of any C implementation of a fast,
|> general purpose exp/log (e.g. table lookup with a few iterations for
|> fine tuning), available publicly or in a book?  Or perhaps a
|> description of a general algorithm that I can implement in C without
|> too many problems?
|>
|> Thanks in advance.
|>
|> Peter K. Campbell
|> [e-mail]

Take a look at "Table-Driven implementation of the exponential function for
IEEE floating-point arithmetic", Ping Tak Peter Tang, ACM Trans. Math. Softw.,
Vol. 15, No. 2 ( June 1989) pp144-157.

------------------------------------------------------------------------
        Donald Frederick       |      Office of Academic Computing
        [e-mail]       |      University of California, Irvine
        [e-mail]    |      Irvine, CA  92717
        [phone]         |      FAX [phone]
-----------------------------------------------------------------------