#1656: Bignum exponentiation yields wrong results
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Reporter: [EMAIL PROTECTED] | Owner:
Type: bug | Status: new
Priority: normal | Milestone: 6.8
Component: Compiler | Version: 6.6
Severity: major | Resolution:
Keywords: | Difficulty: Unknown
Os: Linux | Testcase:
Architecture: x86_64 (amd64) |
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Comment (by [EMAIL PROTECTED]):
This time, I got the same result as with C+gmp, but used a different
program:
{{{
power acc _ 0 = acc
power acc x n | odd n = power (x * acc) (x * x) ((n - 1) `div` 2)
| even n = power acc (x * x) (n `div` 2)
main = let (^^^) = power 1 in do
writeFile "myresult" . show $ 9 ^^^ (9 ^^^ 9)
}}}
Note: this time I used writeFile directly instead of print and redirecting
the output, and I am using an exponentiation algorithm different from the
one in the base library. Although I don't see why that would lead to
different results. (I haven't looked at the base one very much)
I'll try once again with writeFile and the builtin ^, to see whether print
and redirection messed with my number.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1656>
GHC <http://www.haskell.org/ghc/>
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