MR K P SCHUPKE wrote:
Why is there no Irrational class. This would make more sense for
Floats and Doubles than the fraction based Rational class. We could
also add an implementation of infinite precision irrationals using
a pair of Integers for exponent and mantissa.
That would just be a subset of
Henning Thielemann wrote:
I wonder why Infinity has a sign in IEEE floating processing, as well as
0. To support this behaviour uniformly one would need a +0 or -0 offset
for each number, which would lead straightforward to non-standard analysis
...
See Branch Cuts for Complex Elementary
Henning Thielemann wrote:
On Fri, 5 Nov 2004, Robert Dockins wrote:
What IEEE has done is shoehorned in some values that aren't really
numbers into their representation (NaN certainly; one could make a
convincing argument that +Inf and -Inf aren't numbers).
I wonder why Infinity has a sign in
On Thu, Nov 04, 2004 at 08:32:52PM +0100, Sven Panne wrote:
It's an old thread, but nothing has really happened yet, so I'd like to
restate and expand the question: What should the behaviour of toRational,
fromRational, and decodeFloat for NaN and +/-Infinity be? Even if the report
is unclear
With GHCi, I get:
Prelude Ratio toRational (1.0/0) :: Ratio Integer
My guess is because irrationals can't be represented on a discrete
computer (unless you consider a computaion, the limit of which is the
irrational number in question). A single irrational might not just be
arbitrarily long, but it may have an _infinite_ length representation!
What you have
On Fri, 5 Nov 2004, Robert Dockins wrote:
What IEEE has done is shoehorned in some values that aren't really
numbers into their representation (NaN certainly; one could make a
convincing argument that +Inf and -Inf aren't numbers).
I wonder why Infinity has a sign in IEEE floating
My guess is because irrationals can't be represented on a discrete computer
Well, call it arbitrary precision floating point then. Having built in
Integer support, it does seem odd only having Float/Double/Rational...
Keean.
..
___
On Fri, 2004-11-05 at 13:57, Henning Thielemann wrote:
On Fri, 5 Nov 2004, Robert Dockins wrote:
What IEEE has done is shoehorned in some values that aren't really
numbers into their representation (NaN certainly; one could make a
convincing argument that +Inf and -Inf aren't numbers).
[...] Thus (a-b) is not the same as -(b-a) for IEEE floats!
Nor is x*0 equal to 0 for every x; nor does x == y imply f(x) == f(y)
for every x, y, f; nor is addition or multiplication associative. There
aren't many identities that do hold of floating point numbers.
Yes, but they DO hold for
On Fri, Nov 05, 2004 at 02:53:01PM +, MR K P SCHUPKE wrote:
My guess is because irrationals can't be represented on a discrete computer
Well, call it arbitrary precision floating point then. Having built in
Integer support, it does seem odd only having Float/Double/Rational...
There are
-haskell-users-
| [EMAIL PROTECTED] On Behalf Of Sven Panne
| Sent: 08 August 2004 17:02
| To: Hal Daume III
| Cc: GHC Users Mailing List; Malcom Wallace
| Subject: Re: Double - CDouble, realToFrac doesn't work
|
| Hal Daume III wrote:
| [...]
| Prelude Foreign.C (0 :: CDouble) / 0
| NaN
| Prelude
: Double - CDouble, realToFrac doesn't work
|
| Hal Daume III wrote:
| [...]
| Prelude Foreign.C (0 :: CDouble) / 0
| NaN
| Prelude Foreign.C (0 :: Double) / 0
| NaN
| Prelude Foreign.C realToFrac ((0 :: Double) / 0) :: CDouble
| -Infinity
|
| yikes! the NaN got turned into a -Infinity
Hal Daume III wrote:
[...]
Prelude Foreign.C (0 :: CDouble) / 0
NaN
Prelude Foreign.C (0 :: Double) / 0
NaN
Prelude Foreign.C realToFrac ((0 :: Double) / 0) :: CDouble
-Infinity
yikes! the NaN got turned into a -Infinity!!!
aside from manually checking for 'strange' Double/CDouble values and
I need to convert a Double to a CDouble to pass to a C function.
In the past, when I've asked how to do this, I'm told: realToFrac. This
works in most cases, but recently gave me a problem that took me *forever*
to track down:
Prelude Foreign.C (0 :: CDouble) / 0
NaN
Prelude Foreign.C (0 ::
15 matches
Mail list logo
