Modification in besselk (Modified Bessel fn of 2nd kind order zero)

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Waseem Akhtar 2021-7-24

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评论： Waseem Akhtar 2021-7-24

Hi,

As far as I know, besselk in integral form is an integral from 0 to Inf. Is there a way to modify the limits of integration and convert it into a definite integral?

I have tried to evaluate the integral form by using "integral/int" functions but it takes too much time as compared to evaluation of besselk(nu,z). I hope there's a way to change the limits in the syntax of besselk.

Thank you.

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Answer 1

John D'Errico 2021-7-24

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Simple answer - No.

Utilities like this, erf is another excellent example, that while they can be defined in terms of an integral, are not in fact implemented in terms of a numerical integration. Instead, other methods, perhaps a series approximation, are employed to compute the result. And that method will not be changable to allow other limits.