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Accuracy of HP Financial Calculators - Canadian mortgage
04-09-2014, 01:49 PM
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RE: Accuracy of HP Financial Calculators - Canadian mortgage
(04-08-2014 08:19 PM)Dieter Wrote:  Here are the results:

10 digit working precision:
HP method: error within –6 ... +9 ULP
artanh method: error within –6 ... +6 ULP

12 digit working precision:
HP method: error within –6 ... +9 ULP
artanh method: error within –7 ... +8 ULP

16 digit working precision:
HP method: error within –5 ... +8 ULP
artanh method: error within –4 ... +4 ULP

I now found another method of evaluating ln(1+x) using the inverse hyperbolic sine, cf. this message.

Here is how it performs using the same test as above:

10 digit working precision:
arsinh method: error within –5 ... +4 ULP

12 digit working precision:
arsinh method: error within –4 ... +5 ULP

16 digit working precision:
arsinh method: error within –6 ... +5 ULP

So the arsinh method seems even better than the previous one. It also does not have problems with very large x, so that it is my preferred method now.

Dieter
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RE: Accuracy of HP Financial Calculators - Canadian mortgage - Dieter - 04-09-2014 01:49 PM



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