Re: [Boost-bugs] [Boost C++ Libraries] #2671: Calculation overflow for the 4th moment

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #2671: Calculation overflow for the 4th moment
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2009-02-04 17:14:00

#2671: Calculation overflow for the 4th moment
-------------------------------------+--------------------------------------
  Reporter:  m.de.wever_at_[hidden]  |       Owner:  eric_niebler
      Type:  Bugs                    |      Status:  closed      
 Milestone:  Boost 1.38.0            |   Component:  accumulator 
   Version:  Boost 1.37.0            |    Severity:  Showstopper 
Resolution:  wontfix                 |    Keywords:              
-------------------------------------+--------------------------------------
Changes (by eric_niebler):

  * status:  new => closed
  * resolution:  => wontfix

Comment:

 The moment returns a double even for integral sample types because of the
 division at the end. The additions during the accumulation phase are
 integral, and so they overflow. Adding overflow checks would slow down the
 common case, so I'm disinclined to add it unconditionally. Steven is
 right, the easiest solution is for you to use doubles.

 The larger issue is how to handle things like overflow, underflow, divide-
 by-zero, NaN propagation, etc., throughout the Accumulators library (and
 beyond to all the math-related libraries in Boost (and beyond to the
 standard library)). One possibility would be to add checked arithmetic as
 a policy. Another possibility is to specify the sample type as
 checked<int> or something. It's probably worth starting such a discussion
 on the Boost list. I'm sure John Maddock would have some useful insights.

 I'm resolving this bug as "wontfix" and will open a separate feature
 request ticket for better control over error-handling in Accumulators.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/2671#comment:3>
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