[Numpy-discussion] NaN (Not a Number) occurs in calculation of complex number for Bessel functions
Happyman
bahtiyor_zohidov at mail.ru
Fri Dec 21 14:44:10 EST 2012
Thanks
But I could find for Win64 bit windows????
Second question: Did you mean that I have to put lens limits of those number???
Пятница, 21 декабря 2012, 15:45 UTC от Pauli Virtanen <pav at iki.fi>:
>Hi,
>
>Your code tries to to evaluate
>
> z = 1263309.3633394379 + 101064.74910119522j
> jv(536, z)
> # -> (inf+inf*j)
>
>In reality, this number is not infinite, but
>
> jv(536, z) == -2.3955170861527422e+43888 + 9.6910119847300024e+43887
>
>These numbers (~ 10^43888) are too large for the floating point
>numbers that computers use (maximum ~ 10^308). This is why you get
>infinities and NaNs in the result. The same is true for the spherical
>Bessel functions.
>
>You will not be able to do this calculation using any software
>that uses only floating point numbers (Scipy, Matlab, ...).
>
>You need to use analytical properties of your problem to
>get rid of such large numbers. Alternatively, you can use arbitrary
>precision numbers. Python has libraries for that:
>
>http://code.google.com/p/mpmath/
>
>
>By the way, the proper place for this discussion is the following
>mailing list:
>
>http://mail.scipy.org/mailman/listinfo/scipy-user
>
>--
>Pauli Virtanen
>
>
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