Hi, I'm new to Haskell, but I've asked around on some of the freenode communities and nobody there can help me. This may not be a bug, but simply my inexperience.
f :: [a] -> a
f = [u, v] -> (v - (u u u))
grad f [1, 1] works just fine in GHCI
map (\x -> grad x) [f] gives the following error:
Couldn't match type ‘Integer’
with ‘Numeric.AD.Internal.Reverse.Reverse s a’
Expected type: [Numeric.AD.Internal.Reverse.Reverse s a]
-> Numeric.AD.Internal.Reverse.Reverse s a
Actual type: [Integer] -> Integer
• In the first argument of ‘grad’, namely ‘f’
In the expression: grad f
In the first argument of ‘map’, namely ‘(\ f -> grad f)’
• Relevant bindings include
it :: [[a] -> [a]] (bound at :6:1)
I've tried many different ways of partially applying grad to a list of functions but cannot get it to typecheck.
donovancrichton
commented
7 years ago
Hi, I'm new to Haskell, but I've asked around on some of the freenode communities and nobody there can help me. This may not be a bug, but simply my inexperience.
f :: [a] -> a f = [u, v] -> (v - (u u u))
grad f [1, 1] works just fine in GHCI
map (\x -> grad x) [f] gives the following error: Couldn't match type ‘Integer’ with ‘Numeric.AD.Internal.Reverse.Reverse s a’ Expected type: [Numeric.AD.Internal.Reverse.Reverse s a] -> Numeric.AD.Internal.Reverse.Reverse s a Actual type: [Integer] -> Integer • In the first argument of ‘grad’, namely ‘f’ In the expression: grad f In the first argument of ‘map’, namely ‘(\ f -> grad f)’ • Relevant bindings include it :: [[a] -> [a]] (bound at:6:1)
I've tried many different ways of partially applying grad to a list of functions but cannot get it to typecheck.