commons-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Gunel Jahangirova (JIRA)" <j...@apache.org>
Subject [jira] [Created] (NUMBERS-22) Method reciprocal() in Complex for complex numbers with parts very close to 0.0
Date Wed, 19 Apr 2017 12:24:41 GMT
Gunel Jahangirova created NUMBERS-22:
----------------------------------------

             Summary: Method reciprocal() in Complex for complex numbers with parts very close
to 0.0
                 Key: NUMBERS-22
                 URL: https://issues.apache.org/jira/browse/NUMBERS-22
             Project: Commons Numbers
          Issue Type: Improvement
            Reporter: Gunel Jahangirova
            Priority: Minor


I have been redirected here from the issue repository of Apache Commons Math, as the Complex
class will likely be deprecated in favour of its equivalent in "Commons Numbers".

In class Complex method reciprocal() returns INF only if the real and imaginary parts are
exactly equal to 0.0. In the cases when real and imaginary parts are double numbers very close
to 0.0, it does not hold. For example, if we run this code

{code}
Complex complex0 = new Complex((-2.44242319E-315));
Complex complex1 = complex0.reciprocal();
{code}

the value of complex1.getReal() will be -Infinity and the value of complex1.getImaginary()
will be NaN, instead of complex1 being equal to INF.

The suggested solutions after the discussion are either checking the equality to ZERO with
some tolerance or to detect if one of the real or imaginary parts is going to be infinite
or NaN and then return the proper result. 



--
This message was sent by Atlassian JIRA
(v6.3.15#6346)

Mime
View raw message