[Haskell-cafe] Type inference problem with division (/)
noandrews at gmail.com
Tue Oct 30 20:31:25 EDT 2007
I have the following function:
theRemainder :: [String] -> [String] -> Double
theRemainder xs xt = sum( map additional (unique xs) )
additional x = poccur * (inf [ppos,pneg]) --inf takes [Double]
xsxt = zip xs xt
pi = countPos xr -- countPos returns an Int
ni = (length xr) - pi
len = length xs
len2 = length xr
ppos = pi/len2 -- THESE ARE THE PROBLEM
pneg = ni/len2 -- THESE ARE THE PROBLEM
poccur = (pi+ni)/len
xr = (filter ((\y -> (fst y)==x)) (xsxt))
And I am getting this error message with ghc:
Couldn't match expected type `Double' against inferred type `Int'
In the expression: ppos
In the first argument of `inf', namely `[ppos, pneg]'
In the second argument of `(*)', namely `(inf [ppos, pneg])'
How can I change the declaration of ppos nad pneg so they are treated as
Double for the inf function?
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