[Boost-bugs] [Boost C++ Libraries] #11235: Variance error when used with std::complex

Subject: [Boost-bugs] [Boost C++ Libraries] #11235: Variance error when used with std::complex
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2015-04-24 11:20:58

#11235: Variance error when used with std::complex
-------------------------------------------------+-------------------------
 Reporter:  Martín Sanz Sabater <martin.sanz@…>  |      Owner:
     Type:  Bugs                                 |  eric_niebler
Milestone:  To Be Determined                     |     Status:  new
  Version:  Boost 1.58.0                         |  Component:  accumulator
 Keywords:                                       |   Severity:  Problem
-------------------------------------------------+-------------------------
 The result of variance in complex numbers sequence must be real, but it is
 complex.

 It is solved changing the line (in "variance.hpp"):
         this->variance =
                     numeric::fdiv(this->variance * (cnt - 1), cnt)
                   + numeric::fdiv(tmp * tmp, cnt - 1);

 with this one:
         this->variance =
                     numeric::fdiv(this->variance * (cnt - 1), cnt)
                   + numeric::fdiv(std::pow(std::abs(tmp),2), cnt - 1);


 P.D: sorry, I don't know how to fix it in "lazy_variance"

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/11235>
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