[Octave-patch-tracker] [patch #9065] octave::math::min and max template ignore isnan

[Carnë Draug]

URL:
  <http://savannah.gnu.org/patch/?9065>

                 Summary: octave::math::min and max template ignore isnan
                 Project: GNU Octave
            Submitted by: carandraug
            Submitted on: Tue 02 Aug 2016 03:29:36 AM GMT
                Category: None
                Priority: 5 - Normal
                  Status: None
                 Privacy: Public
             Assigned to: None
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any

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Details:

Octaves definition of min is the smallest of the non NaN values, but
liboctave's templated octave::math::min function does not behave that way.
Instead, it behaves like std::min and we have a specialization for double and
float.

This is confusing because: 1) the template behaviour is different from Octave,
2) the specialization actually changes the english definition of Octave's min
(given another type, other than double and low, with a concept of nan, min
would not consider the nan value).  An actual example:


  long double x = 5;
  long double y = NAN;
  double r = octave::math::min (x, y); // incorrectly returns NAN


I tried to change this so that the general template does check for nan, while
keeping the specialization for octave_int.

This caused problems with int and short because they are missing isnan. These
were required because Octave declares MArray<int> and MArray<short> so I
defined isnan for int and short (although I'm not sure why, MArray<int> and
MArray<short>, are not used anywhere and we already have Marray for all the
octave_int --- or why do we have octave_int at all?).




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