[Octave-bug-tracker] [bug #64801] besselj(1, z) is not pure imaginary for pure imaginary inputs

[Lapresté Jean-Thierry]

Follow-up Comment #2, bug #64801 (project octave):

[(Erreur - Introuvable)]
it's surely a bug as the error on the real part seems to tend to infinity as
the i coef increase.

 besselj(1,1.e-300+100i)
ans =  6.541875770923201e+25 + 1.068369390338163e+42i

>>  besseli(1,1.e-300i+100)
ans =  1.068369390338163e+42 - 1.489643709947372e-45i

also the relation between besseli(1,z) and besselj(1,iz) is broken even for
non pure imaginaries.

perhaps as besseli seems correct a workaround would be for n=1 to define
bessej(1,...) in term of besseli ? 

In fact do you use amos fortran here ? Is it the extern implementation which
has problems ?




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