Re: [Haskell-cafe] Unresolved overloading error

It's working now, thank you. I changed the definition to

binom n j = div (fac n) ((fac j)*(fac (n - j)))

bernoulli n p j = fromIntegral(binom n j)*(p ^ j) * ((1 - p)^(n - j))

Lennart Augustsson wrote: The definition of fac forces the result to have the same type as the argument. Then in binom you use / which forces the type to be Fractional. And finally you use ^ which forces the type to be Integral. There is no type that is both Fractional and Integral. I suggest using div instead of / in binom (binomial coefficients are integers after all). And then a fromIntegral applied to the binom call in bernoulli. -- Lennart On Mar 31, 2007, at 10:04 , Scott Brown wrote:

I have written this code in Haskell which gives an unresolved overloading error. The function bernoulli should give the probability of j successes occuring in n trials, if each trial has a probability of p.

...

fac 0 = 1 fac n = n * fac(n - 1)

...

binom n j = (fac n)/((fac j)*(fac (n - j)))

...

bernoulli n p j = (binom n j)*(p ^ j) * ((1 - p)^(n - j))

However, bernoulli 6 0.5 3 gives the error:

ERROR - Unresolved overloading *** Type : (Fractional a, Integral a) => a *** Expression : bernoulli 6 0.5 3

Why doesn't Haskell infer the types? What kind of type casting or type definition can I use to fix the error? Send instant messages to your online friends http:// au.messenger.yahoo.com

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