From: Marc-Andre Lafortune <ruby-core@...>
Date: 2011-09-06T15:04:12+09:00
Subject: [ruby-core:39296] [Ruby 1.9 - Bug #5272][Open] Float#round doesn't round big values


Issue #5272 has been updated by Marc-Andre Lafortune.

Category set to core
Status changed from Assigned to Open
Assignee deleted (Marc-Andre Lafortune)

Yui NARUSE wrote:
> This issue still happends:
> Float("2.5e-22").round(22) #=> 2.0e-22

This is a different issue, caused by calculation error. I opened issue #5273 to deal with boundary cases like this one. This present issue was not due to approximation but by truncation of any values.

Moving back to backport request
----------------------------------------
Bug #5272: Float#round doesn't round big values
http://redmine.ruby-lang.org/issues/5272

Author: Marc-Andre Lafortune
Status: Open
Priority: Normal
Assignee: 
Category: core
Target version: 1.9.3
ruby -v: ruby 1.9.4dev (2011-09-06 trunk 33199) [x86_64-darwin11.1.0]


For large enough values (outside of Fixnum range), Float#round does not round at all but simply truncates:

  2.999999999999999e20.round(-20) # => 200000000000000000000

Fixed in trunk, but would be nice to backport for Ruby 1.9.3.



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