Re: [Boost-bugs] [Boost C++ Libraries] #10658: sym_difference yields bad result for int polygons

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #10658: sym_difference yields bad result for int polygons
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2015-03-28 18:56:53

#10658: sym_difference yields bad result for int polygons
-------------------------------------+-------------------------------------
  Reporter:  Volker Schöch           |      Owner:  barendgehrels
  <vschoech@…>                       |     Status:  new
      Type:  Bugs                    |  Component:  geometry
 Milestone:  Boost 1.58.0            |   Severity:  Regression
   Version:  Boost 1.57.0            |   Keywords:  sym_difference,
Resolution:                          |  polygon, large numbers, domain of
                                     |  definition, integer
-------------------------------------+-------------------------------------
Changes (by mkaravel):

 * cc: mkaravel (added)
 * milestone:  To Be Determined => Boost 1.58.0

Comment:

 The problem was in the computation of the intersection points. In
 particular, integer overflow was taking place, yielding the wrong results.

 The problem has been fixed by locally promoting the coordinates to a
 number type with increased precision, thus avoiding the overflow.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/10658#comment:3>
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