[ruby-core:24133] [Bug #1708] require 'complex' Causes Unexpected Behaviour

Issue #1708 has been updated by tadayoshi funaba.


ruby is a great believer in unix/c.

Math.acosh(-1) # EDOM
(-8) ** 0.5 #=> NaN
1 / 2 #=> 0

and

require 'cmath'
CMath.acosh(-1) #=> (0.0+3.141592653589793i)
Complex(-8) ** 0.5 #=> (1.7318549141438708e-16+2.82842712474619i)
Float(1) / 2 #=> 0.5
Rational(1) / 2 #=> (1/2)

it's too hard.

in scheme:

(acosh -1) ;=> 0.0+3.141592653589793i
(expt -8 0.5) ;=> 1.7318549141438708e-16+2.82842712474619i
(/ 1 2) ;=> 1/2

it's so simple.

i think that introducing complex number means extending the domain of ruby's numeric system.
we should provide proper results in the domain.
we should not restrict any general operations.

we can always use "div" instead of "/" for integer division.
and we can also provide FMath.sqrt as a restricted version, if you want.

of course, this is an option.
i'm looking forward to 2.0.
----------------------------------------
http://redmine.ruby-lang.org/issues/show/1708

----------------------------------------
http://redmine.ruby-lang.org