Lower memory use of instance Arbitrary Double/Float.
#419
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ghci> flip traverse [1..100] $ \_ -> length . show <$> generate (scale (const 100000000) $ (arbitrary :: Gen Double)) on master, this is slow and memory hungry. (I couldn't figure out how to pass RTS options to ghci using `cabal repl`, but I've seen it take over 5 minutes and 10 GB.) With this commit it's fast. Closes nick8325#418.
src/Test/QuickCheck/Arbitrary.hs
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| i <- chooseInt (0, n) | ||
| pure (fromRational (streamNth i rationalUniverse)) | ||
| pure (fromRational (streamNth (min i 256) rationalUniverse)) |
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This creates a strange distribution of min i 256. Better to do i <- chooseInt (0, min n 256).
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Yeah, I wasn't sure about that. I went with this on grounds "larger size means you still get bigger things here on average", but happy to change.
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The problem with the old code is that larger size => n is almost always bigger than 256 => the result is almost always the same.
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on master, this is slow and memory hungry. (I couldn't figure out how to pass RTS options to ghci using
cabal repl, but I've seen it take over 5 minutes and 10 GB.) With this commit it's fast.Closes #418.