On Wed, 27 Jul 2011, dokondr wrote:
In your example:
1) I would use:
dot = dot' * dot'
dot' = sum . elems . intersectionWith (*)
norm = sum . fmap (**2) . elems
instead of:
dot = sum . elems . intersectionWith (*)
norm = (**0.5) . sum . fmap (**2) . elems
2) I don't understand the syntax:
cosineSimilarity <$> lookup x space <*> lookup y space
What are <$> and <*>?
They are from Control.Applicative and are applied to a Maybe type here. It
means that cosineSimilarity is applied to the result of looking up 'x' and
'y' in space. If 'x' or 'y' is not in space, then
cosineSimilarity <$> lookup x space <*> lookup y space
is Nothing.
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