#17678: special values of Bessel functions
-------------------------------------+-------------------------------------
       Reporter:  rws                |        Owner:
           Type:  enhancement        |       Status:  needs_review
       Priority:  minor              |    Milestone:  sage-6.5
      Component:  symbolics          |   Resolution:
       Keywords:                     |    Merged in:
        Authors:  Ralf Stephan       |    Reviewers:
Report Upstream:  N/A                |  Work issues:
         Branch:                     |       Commit:
  u/rws/special_values_of_bessel_functions|  
191ca289d3c26813e0244251a983a62f2057347a
   Dependencies:                     |     Stopgaps:
-------------------------------------+-------------------------------------
Changes (by {'newvalue': u'Ralf Stephan', 'oldvalue': ''}):

 * cc: chapoton (added)
 * commit:   => 191ca289d3c26813e0244251a983a62f2057347a
 * status:  new => needs_review
 * author:   => Ralf Stephan


Old description:

> At the moment everything Bessel is sent to mpmath and returns floating
> point but I,,n,,(0) and J,,n,,(0) are in (0,1). Also all I/J/K/Y,,n,,(x)
> with n in (-1/2,1/2) is a simple expression.
>
> For the latter see p.10 of
> http://www.math.psu.edu/papikian/Kreh.pdf

New description:

 At the moment everything Bessel is sent to mpmath and returns floating
 point but I,,n,,(0) and J,,n,,(0) are in (0,1). Also all I/J/K/Y,,n,,(x)
 with n in (-1/2,1/2) is a simple expression.

 For the latter see p.10 of
 http://www.math.psu.edu/papikian/Kreh.pdf

 This allows exact computation of series:
 {{{
 sage: bessel_I(2,x).series(x,10)
 1/8*x^2 + 1/96*x^4 + 1/3072*x^6 + 1/184320*x^8 + Order(x^10)
 }}}

--

Comment:

 New commits:
 
||[http://git.sagemath.org/sage.git/commit/?id=191ca289d3c26813e0244251a983a62f2057347a
 191ca28]||{{{17678: special values of Bessel functions}}}||

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Ticket URL: <http://trac.sagemath.org/ticket/17678#comment:2>
Sage <http://www.sagemath.org>
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