From: Alex Young <alex@...>
Date: 2011-03-18T22:24:57+09:00
Subject: [ruby-core:35526] [Ruby 1.9 - Bug #4510][Open] Float#round(n) is O(n)


Issue #4510 has been reported by Alex Young.

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Bug #4510: Float#round(n) is O(n)
http://redmine.ruby-lang.org/issues/4510

Author: Alex Young
Status: Open
Priority: Normal
Assignee: 
Category: 
Target version: 
ruby -v: ruby 1.9.2p136 (2010-12-25 revision 30365) [i686-linux]


The current implementation of Float#round(n) is O(n). This causes a minor issue with rubyspec, which includes this:

  0.8346268.round(-2.0**30).should == 0

which would take about 5 minutes to complete on my machine, during which time the interpreter is locked, doesn't respond to signals, and certainly won't brook any Timeout interruption.

Attached is a patch to replace the problematic part with a call to pow(3).


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