[Scipy-tickets] [SciPy] #1465: SciPy output fo mathieu_a and mathieu_b differs from GSL for q < 0

SciPy Trac scipy-tickets@scipy....
Thu Jun 30 05:27:18 CDT 2011


#1465: SciPy output fo mathieu_a and mathieu_b differs from GSL for q < 0
---------------------------+------------------------------------------------
 Reporter:  Nikolay        |       Owner:  pv    
     Type:  defect         |      Status:  new   
 Priority:  normal         |   Milestone:  0.10.0
Component:  scipy.special  |     Version:  0.9.0 
 Keywords:  mathieu        |  
---------------------------+------------------------------------------------
Changes (by pv):

  * milestone:  Unscheduled => 0.10.0


Comment:

 I suspect the status here is the same as for `mathieu_sem` -- the specfun
 implementation of the Mathieu functions is valid only for `q >= 0`, (this
 is, however, not marked in the source code.), but instead returns garbage,
 which Scipy happily passes on to the user.

 The short-term fix is to make Scipy return `nan` for all Mathieu functions
 when `q < 0`. The long-term fix is to write or find an implementation
 suitable for these values of `q`.

-- 
Ticket URL: <http://projects.scipy.org/scipy/ticket/1465#comment:3>
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