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MathGroup Archive 1993

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Bugs in Mma functions on the NeXT

  • To: mathgroup at yoda.physics.unc.edu
  • Subject: Bugs in Mma functions on the NeXT
  • From: herrmann at siam.math.tamu.edu (joe herrmann)
  • Date: Wed, 10 Feb 1993 17:07:27 -0600

Dear Mathgroup,

I installed Mma 2.1 for the NeXT which I ran under NeXTStep OS 2.1 to
 fix the bugs in Mma 2.0 that E^(-625000)= 1.40101 10^22,  E^(-670000)=
2.51105 10^56, etc.  Mma 2.1 fixed these particular values and others I
identified but I have found the values given below are still incorrect
in Mma 2.1 under NeXTStep OS 2.1.    However all exponential bugs I am
aware of are fixed in Mma 2.0 or 2.1 by upgrading to NeXTStep OS 3.0.

However, I found a bug in BesselJ in 3.0 as can be seen in the
following:  BesselJ[177.4,28.-.28I]=0. + 0. I  and
BesselJ[177.4,28.]=0.   The first is definitely wrong since all zeros
of BesselJ with order greater than -1 are real, moreover for Mma 2.0 on
NeXT OS 2.1 and for Mathematica (MIPS) I find

                                      -121
 BesselJ[177.4,28.]= 2.513042235631 10
 
                                          -122                   -121
BesselJ[177.4,28.-.28I]= -4.56550333659 10     - 2.49427565746 10     I  

Exponential bugs in Mma 2.1 under NeXTStep OS 2.1:

Table[{x,N[E^x]},{x,-300000,-200000,5000}]
                           -130289
{{-300000, 4.5230253774 10       },



                     -71
  {-295000, 4.1807 10   },



                           -125946
  {-290000, 3.9833462329 10       },



                           -102060
  {-235000, 6.2625720561 10       },



                      -296
  {-230000, 1.05042 10    },



                           -97717
  {-225000, 5.5153333723 10      },


Sincerely,

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





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