#82: Not a Number

[GHC-2]

#82: Not a Number
--------------------+-------------------------------------------------------
 Reporter:  guest   |       Owner:  nobody
     Type:  defect  |      Status:  new  
 Priority:  minor   |   Milestone:        
Component:  hugs    |     Version:  200609
 Keywords:          |  
--------------------+-------------------------------------------------------
 My Program was:

 {{{
 cosineSeries :: Float -> [Float]
 cosineSeries x = scanl  (cosineSerPartSum x) 1 [1..]

 cosineSerPartSum :: Float -> Float -> Integer -> Float
 cosineSerPartSum x prev i = prev + ((-1) ^ i) * (x ^ (2 * i)) /
 fromIntegral (fak (2 * i))

 fak :: Integer -> Integer
 fak n = product [1..n]
 }}}

 My Study Mate is running WinHugs and when he types "cosineSeries 2" he
 gets many Numbers....
 I am Running hugs98 on a Mac. Im getting something like this:

 Main> cosineSeries 2
 [1.0,-1.0,-0.3333333,-0.4222222,-0.415873,-0.4161552,-0.4161466,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,-0.4161468,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,çnan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,nan,^C{Interrupted!}

--
Ticket URL: <http://hackage.haskell.org/trac/hugs/ticket/82>
Hugs <http://www.haskell.org/hugs/>
Hugs 98, an interpreter for Haskell
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[GHC-2]

#82: Not a Number
----------------------+-----------------------------------------------------
  Reporter:  guest    |       Owner:  nobody
      Type:  defect   |      Status:  closed
  Priority:  minor    |   Milestone:        
 Component:  hugs     |     Version:  200609
Resolution:  invalid  |    Keywords:        
----------------------+-----------------------------------------------------
Changes (by ross):

  * status:  new => closed
  * resolution:  => invalid

Comment:

 That is to be expected: factorial 35 is to big to fit in a Float.  You'd
 get up to 170 if you used Double instead (and old versions of Hugs used
 the C double type internally for both types).  But a better approach would
 be to use another scanl to build the terms of the series incrementally as
 Floats or Doubles, before the scanl you're using to get partial sums.

--
Ticket URL: <http://hackage.haskell.org/trac/hugs/ticket/82#comment:1>
Hugs <http://www.haskell.org/hugs/>
Hugs 98, an interpreter for Haskell
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