[jruby-dev] [jira] (JRUBY-6889) Float format string rounding tie breaker strategy does not match MRI

[Ben Armstrong (JIRA)]

Ben Armstrong created JRUBY-6889 Float format string rounding tie breaker strategy does not match MRI Issue Type: Bug Affects Versions: JRuby 1.7.0.pre2, JRuby 1.6 Assignee: Thomas E Enebo Created: 12/Sep/12 9:27 AM Description: In MRI (several versions, including at least 1.8.7p358 and 1.9.3p194) the rounding tie breaker strategy used for floating point format strings is "round half to even", whereas in JRuby it is "round half away from zero", as can be seen in the following example code. This is different from Float#round in both implementations, which appears to adopt the "round half away from zero" strategy. http://en.wikipedia.org/wiki/Rounding#Round_half_to_even http://en.wikipedia.org/wiki/Rounding#Round_half_away_from_zero MRI: (-3...3).map{|i|f=i+0.5; [f,'%1.0f' % f,f.round]} => [[-2.5, "-2", -3], [-1.5, "-2", -2], [-0.5, "-0", -1], [0.5, "0", 1], [1.5, "2", 2], [2.5, "2", 3]] JRuby: (-3...3).map{|i|f=i+0.5; [f,'%1.0f' % f,f.round]} => [[-2.5, "-3", -3], [-1.5, "-2", -2], [-0.5, "-1", -1], [0.5, "1", 1], [1.5, "2", 2], [2.5, "3", 3]] Project: JRuby Priority: Minor Reporter: Ben Armstrong

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