Issue #6986 has been updated by shyouhei (Shyouhei Urabe).

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


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Bug #6986: Inconsistent result of BigDecimal#power
https://bugs.ruby-lang.org/issues/6986#change-29203

Author: phasis68 (Heesob Park)
Status: Assigned
Priority: Normal
Assignee: mrkn (Kenta Murata)
Category: ext
Target version: 
ruby -v: ruby 2.0.0dev (2012-09-05 trunk 36913) [i386-mswin32_100]


I found BigDecimal#power returns incorrect result for a large value.

C:\tmp>ruby -rbigdecimal -e "p BigDecimal('1e-10').power(1e7)"
#<BigDecimal:a2bdb8,'0.1E-99999999',9(100000026)>

C:\tmp>ruby -rbigdecimal -e "p BigDecimal('1e-10').power(1e8)"
-e:1:in `power': failed to allocate memory (NoMemoryError)
        from -e:1:in `<main>'
	
C:\tmp>ruby -rbigdecimal -e "p BigDecimal('1e-10').power(1e10)"
#<BigDecimal:f7cb3c,'0.0',9(18)>

C:\tmp>ruby -rbigdecimal -e "p BigDecimal('1e-10').power(1e19)"
#<BigDecimal:f7cb3c,'Infinity',9(18)>




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