Re: problem with the exponential function on the NeXT
- To: mathgroup at yoda.physics.unc.edu
- Subject: Re: problem with the exponential function on the NeXT
- From: me at leidecker.gsfc.nasa.gov
- Date: Tue, 29 Dec 92 09:52:00 -0500
Joe Herrmann writes that he used his NeXT and Mma to evaluate
Table[N[E^x],{x,-700000,-600000,5000}], and then found *wrong* results
for x=-670,000 and x=-625,000. However, correct results were observed
when running on a friend's Sun.
I just evaluated the expression on my NeXT, and did not get the reported
wrong values --- all of them looked fine. And my friend, Charles Powers,
just ran the full expression on his NeXT --- all the values look fine.
In particular, we both get E^(-670,000)=4.97880161*10^(-290978). (Other
values supplied on request.)
I am running Mma ver. 1.2 (I'll get around to upgrading someday) on a
Cube with the 25 MHz 040 board, and NeXTstep 3.0; and Powers is running
Mma ver. 2.1 on a NeXTstation with a 33 MHz 040, and NeXTstep 3.0.
NeXTstep 2.0 had a bug in the routines that the 040's internal math
co-processor used to handle the transcendentals --- perhaps Joe found
something like that?
Regards,
Henning Leidecker