#3134: encodeFloat . decodeFloat
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Reporter: roland | Owner:
Type: bug | Status: new
Priority: normal | Milestone: _|_
Component: Prelude | Version: 6.10.1
Severity: normal | Resolution:
Keywords: | Difficulty: Unknown
Testcase: | Os: Unknown/Multiple
Architecture: Unknown/Multiple |
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Changes (by simonmar):
* difficulty: => Unknown
* milestone: => _|_
Comment:
Interesting, I thought we had a very old ticket about this, but I can't
seem to find it.
Anyway, I suppose the issue is what the representation of NaN and Infinity
should be in the output of `decodeFloat`. There is no provision for NaN
and Infinity in the Haskell definition of `encodeFloat` and `decodeFloat`:
The function decodeFloat applied to a real floating-point number returns
the
significand expressed as an Integer and an appropriately scaled exponent
(an Int).
If decodeFloat x yields (m,n), then x is equal in value to mbn, where b
is the
floating-point radix, and furthermore, either m and n are both zero or
else
bd-1<=m<bd, where d is the value of floatDigits x. encodeFloat performs
the
inverse of this transformation.
from Section 6.4.6, [http://haskell.org/onlinereport/basic.html]
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/3134#comment:1>
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