From: "nobu (Nobuyoshi Nakada)" <noreply@...>
Date: 2022-04-18T08:57:55+00:00
Subject: [ruby-core:108276] [Ruby master Bug#18677] BigDecimal#power (**) returns FloatDomainError when passing an infinite parameter

Issue #18677 has been updated by nobu (Nobuyoshi Nakada).

Assignee set to mrkn (Kenta Murata)
Status changed from Open to Assigned

----------------------------------------
Bug #18677: BigDecimal#power (**) returns FloatDomainError when passing an infinite parameter
https://bugs.ruby-lang.org/issues/18677#change-97298

* Author: dorianmariefr (Dorian Mari��)
* Status: Assigned
* Priority: Normal
* Assignee: mrkn (Kenta Murata)
* ruby -v: ruby 3.1.1p18 (2022-02-18 revision 53f5fc4236) [x86_64-darwin21]
* Backport: 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN
----------------------------------------
Example:

```ruby
> BigDecimal(10) ** BigDecimal("Infinity")
FloatDomainError: Computation results in 'Infinity'
```

Maybe:

```ruby
require "bigdecimal/util"

class BigDecimal < Numeric
  def **(other)
    if other.infinite? == 1
      if self > 1
        BigDecimal::INFINITY
      elsif self == 1
        self
      elsif self >= 0
        BigDecimal(0)
      else
        power(other)
      end
    else
      power(other)
    end
  end
end

def puts_and_eval(string)
  puts string
  p eval(string)
end

puts_and_eval "10 ** BigDecimal::INFINITY"
puts_and_eval "1 ** BigDecimal::INFINITY"
puts_and_eval "0.1 ** BigDecimal::INFINITY"
puts_and_eval "0 ** BigDecimal::INFINITY"
puts_and_eval "-1 ** BigDecimal::INFINITY"
```

Seems like ruby is doing very different things from math though



-- 
https://bugs.ruby-lang.org/

Unsubscribe: <mailto:ruby-core-request@ruby-lang.org?subject=unsubscribe>
<http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-core>