Haskell non exhaustive patterns in function for recursion -


it gives multiple declaration of "mph"

here code 

dotproduct x y = sum(zipwith (*) x y)  matrixproduct x y = mph [] x y  mph acc [] b = acc  counthelp countacc c [] = countacc  counthelp countacc c (d:ds) = counthelp ((dotproduct c d) : countacc) c ds  mph acc (a:as) b = mph ((counthelp [] b) : acc) b

can explain little bit me? suppose input 

x = [[1,2,3],[4,5,6]] y = [[7,9,11],[8,10,12]] matrixproduct x y

it should give martix [[64,58],[154,139]]

what think each time taking out first list of first matrix when the matrix become empty list recursion stop.


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