Sébastien Brisard created MATH-821:
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Summary: SparseRealVectorTest.testMap and testMapToSelf fail
because lost sign of zero entries
Key: MATH-821
URL: https://issues.apache.org/jira/browse/MATH-821
Project: Commons Math
Issue Type: Bug
Affects Versions: 3.0
Reporter: Sébastien Brisard
Mapping {{Inverse}} to an {{OpenMapRealVector}} can lead to wrong answers,
because {{1.0 / 0.0}} should return {{+/-Infinity}} depending on the sign of
the zero entry. Since the sign is lost in {{OpenMapRealVector}}, the answer
must be wrong if the entry is truly {{-0.0}}.
This is a difficult bug, because it potentially affects any function passed to
{{OpenMapRealVector.map()}} or {{mapToSelf()}}. I would recommend we relax the
requirements in the unit tests of this class, and make people aware of the
issue in the class documentation.
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