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From: madler@kanga.caltech.edu (Mark Adler)
Newsgroups: comp.sys.next
Subject: Re: NeXT Mathematica Bug
Message-ID: <1991Mar4.052345.19921@nntp-server.caltech.edu>
Date: 4 Mar 91 05:23:45 GMT
References: <1991Mar3.053006.2986@math.ucla.edu> <1991Mar4.035543.19802@wam.umd.edu>
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Organization: California Institute of Technology, Pasadena
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The following program:

     #include <stdio.h>
     #include <math.h>

     void main(void)
     {
       printf("%g %g\n", tanh(-1.73287), tanh(-1.73288));
     }

when compiled and run under 2.0, gives the result:

     -0.939394 -0.939395

(correct) on a 68030 NeXT running 2.0, but incorrectly gives:

     -0.939394 -1.060605

on a 68040 NeXT, using the very same binary executable.  Wolfram's
comment was: "Mathematica (apparently mistakenly) relies on built-in
math functions."  Gee, I guess so.

This is not the only problem with math on the 68040 (see Bing Chen's
quick-and-easy-way-to-completely-hang-your-NeXT-so-that-not-even-command-
alternate-*-works-using-only-simple-floating-point-division-operations).
I have absolutely no confidence in any numerical results my newly upgraded
NeXT gives me, and I have complained mightily in a message to bug_next@
next.com.  I think I may call them tommorrow and ask for my 030 board
back and see if that gets their attention.

I sure do hope that all of the math problems can be handled simply
by a software upgrade ...

Mark Adler
madler@pooh.caltech.edu