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mathematica [anomaly]

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  • Subject: [mg30817] mathematica [anomaly]
  • From: Ioan Alexandre Romoscanu <romoscanu at>
  • Date: Wed, 19 Sep 2001 00:17:11 -0400 (EDT)
  • Organization: Swiss Federal Institute of Technology (ETHZ)
  • Sender: owner-wri-mathgroup at


Some of you might find the Mathematica behaviour represented in the
linked image surprising if not even worse.

I have a function PerturbationShearRate, which depends of various
parameters (which are kept constant here), and the position coordinate

I choose to plot the  function PerturbationShearRate with constant
parameters but z, i.e. I plot
 PerturbationShearRate[z] for z between 0.999 and 1.001. The value of

I see this result.

In other words, the graph shows that the function PerturbationShearRate
gives values around -268. If now I coose to sample some values in the
same z range with Table[ ], the same Kernel says the values are around

I am quite worried with this all. I do not ask Mathematica to agree with
the Physics, but just to agree with itself. It is a matter of fact that
Mathematica is contradicting itself in this issue.

I considered the option that the function is very oscillatory. However,
changing the sampling in "Table" shoudl give oscillatory results.

Any clue?

Thanks in advance

I. Romoscanu

ioan alexandre romoscanu          - institut für mechanik
CLA G31, eth zentrum,              8092 zürich, schweiz
tel. +41 1 632 77 54,                    +41 76 323 63 05
fax.+41 1 632 11 45,  romoscanu at
nestlé research center
H 212
1000 lausanne 26
tel.  +41 21 785 83 65             fax. +41 21 785 85 53

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