From: Kenta Murata <muraken@...>
Date: 2011-08-10T19:20:31+09:00
Subject: [ruby-core:38891] [Ruby 1.9 - Bug #5179] Complex#rationalize and to_r with approximate zeros


Issue #5179 has been updated by Kenta Murata.

Assignee set to Kenta Murata

0.0 doesn't exactly represent zero. It may be 0.0+-10.0**(Float::MIN_10_EXP-17).
BigDecimal(0) doesn't exactly represent zero, too.

I believe this issue should be resolved by introducing Numeric#exact? and/or Numeric#inexact? methods.

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Bug #5179: Complex#rationalize and to_r with approximate zeros
http://redmine.ruby-lang.org/issues/5179

Author: Marc-Andre Lafortune
Status: Open
Priority: Normal
Assignee: Kenta Murata
Category: core
Target version: 
ruby -v: r32354


Currently, Complex#rationalize and Complex#to_r raise a RangeError if the imaginary part is nonzero *or is a Float*. Note that a BigDecimal(0) is accepted, though:

    Complex(1, 0).to_r                 # => Rational(1,1)
    Complex(1, BigDecimal("0.0")).to_r # => Rational(1,1)
    Complex(1, 0.0).to_r               # => RangeError

This is inconsistent. I recommend not raising an error for 0.0 (Float or BigDecimal). Any objection?



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