       problem with the exponential function on the NeXT

• To: mathgroup at yoda.physics.unc.edu
• Subject: problem with the exponential function on the NeXT
• From: herrmann at siam.math.tamu.edu (joe herrmann)
• Date: Sat, 26 Dec 1992 16:54:36 -0600

```Dear math group,
I found this working on my research about the energy input to cracks in
inhomogeneous materials.  I was using Airy functions and got a strange value at one point.
After checking Abramowitz and Stegun (p148) (10.4.59) I tried their asymptotic formula for
the Airy function and found what was happening was a problem with the exponential
function.

Mathematica 2.0 for NeXT

In

Table[N[E^x],{x,-700000,-600000,5000}]

Out
-304007                -301835
{7.288996199 10       , 2.163103201 10       ,

-299664                -297492
6.419286457 10       , 1.905005669 10       ,

-295321                -293149
5.653348896 10       , 1.677703865 10       ,

56                 -288806
2.51105 10  , 1.4775232975 10       ,

-286635                 -284463
4.384740076 10       , 1.3012279106 10       ,

-282292                 -280120
3.861560881 10       , 1.1459677678 10       ,

-277949                 -275777
3.400806475 10       , 1.0092329824 10       ,

-273606            22
2.995028445 10       , 1.40101 10  ,

-269263                -267092
2.637667109 10       , 7.827615781 10       ,

-264920                -262749
2.322945477 10       , 6.893638932 10       ,

-260577
2.045775856 10       }

Note the incorrect results at -670,000 and -625,000.  I had a friend check this on his Sun
and mathematica gave no incorrect answers in his test so it may only be a problem on the
NeXT.

Can you tell me what is happening?  Is there a fix?

Thank you.

Sincerely,

Joe Herrmann
Texas A&M Math Dept
herrmann at siam.tamu.edu

```

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