* Tsunkiet Man <temp.t...@gmail.com> [2009-02-05 12:37:22+0100] > Hello, > > I'm new to Haskell and it seems like a very nice language to learn. However > I'm not really familiar with the errormessages it produces. I am using a > Helium interpreter. I've created the following module (however it is just a > small sketch). I've written the following code: > > fac :: Int -> Int > fac n = product[1..n] > > boven :: Int -> Int -> Int > boven n k = (fac n) `div` fac k * fac (n-k) > > bin :: Int -> Int -> Int -> Int > bin n k p |(n-k)>0 && k>0 = (boven n k) * (p^k) * (1-p)^(n-k) > |(n-k)<0 && k>0 = (boven n k) * (p^k) * (1/((1-p)^(-(n-k)))) > |(n-k)<0 && k<0 = (boven n k) * (1/(p^(-k))) * > (1/((1-p)^(-(n-k)))) > > When I load this into my interpreter it says: > > Compiling ./Test.hs > (11,55): Type error in infix application > expression : 1 / ((1 - p) ^ (-(n - k))) > operator : / > type : Float -> Float -> Float > does not match : Int -> Int -> Int > (12,47): Type error in infix application > expression : 1 / (p ^ (-k)) > operator : / > type : Float -> Float -> Float > does not match : Int -> Int -> a > (12,62): Type error in infix application > expression : 1 / ((1 - p) ^ (-(n - k))) > operator : / > type : Float -> Float -> Float > does not match : Int -> Int -> a
You can't use fractional division (/) with integers. You can convert integers to fractions using fromIntegral. E.g.: 1 / fromIntegral ((1 - p) ^ (-(n - k))) (literals like 1 doesn't need to be converted because they are polymorphic) -- Roman I. Cheplyaka :: http://ro-che.info/ "Don't let school get in the way of your education." - Mark Twain _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe