On Tue 2008-09-02 09:46, Patrick Perry wrote:
Jed Brown wrote:
The idea with QC is that you start with `simple' random input and progress to more `complicated' input. If say, you are testing a function that builds a list with length equal to the output of the QC-generated function (Double->Int) (with positive precondition) you could be building a huge list very early. This wouldn't happen with other types since `simple' QC-generated functions for, say, (Int->Int) will map small integers to small integers.
I don't think this has anything to do with the definition of coarbitrary. As I understand things: coarbitrary is a function of type x -> StdGen arbitrary is a function of type StdGen -> Int -> x For the type "x -> y", arbitrary is equal to \g n -> (\x -> let g' = coarbitrary x in arbitrary g' n)
I did an experiment in QC1 (with patch). Here are two properties: prop_f (f :: Double -> Int) x = trace (show $ f x) True prop_g (f :: Int -> Int) x = trace (show $ f x) True
Below is the output. Do you think that one is "more simple" than the other?
Hmm, I guess I should have run the test before speculating. It looks like the logarithmic factor keeps it all in control. Jed