On 10/30/07, noa wrote:

Hi!

I have the following function:

theRemainder :: [String] -> [String] -> Double theRemainder xs xt = sum( map additional (unique xs) ) where additional x = poccur * (inf [ppos,pneg]) --inf takes [Double] where 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:

matrix.hs:54:31: 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?

ppos = pi/len2; pi and len2 are both Ints, so dividing them gives you an Int. To convert to a Double, write ppos = fromIntegral (pi/len2). (Type :t fromIntegral in ghci to see what else fromIntegral can be used for.) Cheers, Tim -- Tim Chevalier * catamorphism.org * Often in error, never in doubt "After three days without programming, life becomes meaningless." -- James Geoffrey

On Tue, 30 Oct 2007, noa wrote:

I have the following function:

theRemainder :: [String] -> [String] -> Double theRemainder xs xt = sum( map additional (unique xs) ) where additional x = poccur * (inf [ppos,pneg]) --inf takes [Double] where xsxt = zip xs xt pi = countPos xr -- countPos returns an Int ni = (length xr) - pi len = length xs

-> genericLength

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))