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Precision problem in analytic expression
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Wieland Brendel
Jul 2, 2009, 7:12:00 AM7/2/09
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Dear all,
I have a problem with some analytic expressions. I want to plot them for
different parameters. However, for a certain range of parameters some
terms in the expressions get really large. Although these terms cancel
out in the end, numerical precision seems to be too small resulting in
some differences to the expected result: where it should be (almost)
exactly one in the end the result is actually 1.000056 (= desaster...).
I have a problem with some analytic expressions. I want to plot them for
different parameters. However, for a certain range of parameters some
terms in the expressions get really large. Although these terms cancel
out in the end, numerical precision seems to be too small resulting in
some differences to the expected result: where it should be (almost)
exactly one in the end the result is actually 1.000056 (= desaster...).
There is one term (a csch^2) that goes with 10^15, other elementary
terms range up to 10^9. I tried to set $MinPrecision to higher values
but that changed nothing. I also splitted the term in smaller units and
simplified them - same result.
How can get a higher precision in the calculation and how can I find the
term that produces the troubles. I'm not able to localize the problem.
A big thanks in advance, I am really stuck with that!
With best greetings from germany,
Wieland
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