Re: [Boost-bugs] [Boost C++ Libraries] #7177: Students t returns rubbihs values for undefined input instead of throw

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #7177: Students t returns rubbihs values for undefined input instead of throw
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2012-08-02 08:59:16

#7177: Students t returns rubbihs values for undefined input instead of throw
--------------------------------------+-------------------------------------
  Reporter:  pbristow                 |       Owner:  pbristow       
      Type:  Bugs                     |      Status:  closed         
 Milestone:  Boost 1.52.0             |   Component:  math           
   Version:  Boost Development Trunk  |    Severity:  Problem        
Resolution:  fixed                    |    Keywords:  math students t
--------------------------------------+-------------------------------------
Changes (by pbristow):

  * status:  new => closed
  * version:  Boost 1.50.0 => Boost Development Trunk
  * resolution:  => fixed

Comment:

 After much discussion, we decided to make all moments when df =< moment
 index k throw domain error (and return NaN is the throw is ignored by a
 policy).

 Sources are unclear on this, Wikipedia claiming variance should be ∞ for 1
 < \nu ≤ 2, etc.
 but this probably only applies if df is integral and this package allows
 real values.

 And no practical use of having a return of infinity rather than NaN was
 proposed.

 So, in the absence of a good case, we have Kept It Simple Sirs and
 returned quiet_NaN.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/7177#comment:1>
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