Representations of the complex numbers
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Key: MATH-667
URL: https://issues.apache.org/jira/browse/MATH-667
Project: Commons Math
Issue Type: Wish
Reporter: Gilles
Priority: Minor
Fix For: 3.1
Several issues have been raised about the current behaviour of the "Complex"
class, located in package "o.a.c.m.complex" (e.g. MATH-657, MATH-620).
The ensuing discussion revealed various, sometimes incompatible, requirements
with focus on efficiency or consistency or backwards compatibility or
comparison with other math packages (Octave) or faithfulness to standards
(C99x).
It is thus proposed to create several classes, each with a clearly defined
purpose.
The consensus seems to be that the first task is to implement a new
"BasicComplex" class where the computational formulae (for computing real and
imaginary part of a complex) will be applied directly without worrying about
limiting cases (NaNs and infinities). Doing so will automatically produce a
behaviour similar to the Java {{double}} primitive. It is also assumed that it
will be the most efficient implementation for "normal" use (i.e. not involving
limiting cases).
This task would consist in copying most of the code in the existing "Complex"
class over to "BasicComplex". And similarly with "ComplexTest". Then, in
"BasicComplex", one would remove all variables that refer to NaNs and
infinities together with checks and special assignments, and adapt the unit
tests along the way.
A new "ExtendedComplex" class would inherit from "BasicComplex". This class
would aim at representing the compactified space of the complex numbers (one
point-at-infinity).
A new "C99Complex" class would inherit from "BasicComplex". This class would
aim at implementing the C99x standard.
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