[GHC] #14377: some results not expected with the addition

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Sun Oct 22 18:47:07 UTC 2017


#14377: some results not expected with the addition
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        Reporter:  vanto             |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.2.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Incorrect result  |  Unknown/Multiple
  at runtime                         |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by svenpanne):

 A tiny bit of googling would have showed that the problem is not easy at
 all, see e.g. the 2nd part of https://cs.stackexchange.com/a/81039 or the
 2nd volume of Knuth's TAOCP (Radix Conversions). Apart from the fact that
 numeric algorithms are notoriously hard, there are tradeoffs here, e.g.
 speed vs. "minimality" of the resulting string. Different implementations
 just choose different points in the design space, so GHC's behavior is not
 a bug at all and I propose to close this ticket. Remember: If there was a
 single, universally "right" way to convert binary floats to a decimal
 string, people probably wouldn't write papers/blogs/etc. about it for
 several decades...

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14377#comment:6>
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