RosettaCodeData/Task/Matrix-arithmetic/Haskell/matrix-arithmetic.hs

40 lines
1.2 KiB
Haskell

s_permutations :: [a] -> [([a], Int)]
s_permutations = flip zip (cycle [1, -1]) . (foldl aux [[]])
where aux items x = do
(f,item) <- zip (cycle [reverse,id]) items
f (insertEv x item)
insertEv x [] = [[x]]
insertEv x l@(y:ys) = (x:l) : map (y:) (insertEv x ys)
elemPos::[[a]] -> Int -> Int -> a
elemPos ms i j = (ms !! i) !! j
prod:: Num a => ([[a]] -> Int -> Int -> a) -> [[a]] -> [Int] -> a
prod f ms = product.zipWith (f ms) [0..]
s_determinant:: Num a => ([[a]] -> Int -> Int -> a) -> [[a]] -> [([Int],Int)] -> a
s_determinant f ms = sum.map (\(is,s) -> fromIntegral s * prod f ms is)
determinant:: Num a => [[a]] -> a
determinant ms = s_determinant elemPos ms.s_permutations $ [0..pred.length $ ms]
permanent:: Num a => [[a]] -> a
permanent ms = sum.map (prod elemPos ms.fst).s_permutations $ [0..pred.length $ ms]
result ms = do
putStrLn "Matrice:"
mapM_ print ms
putStrLn "Determinant:"
print $ determinant ms
putStrLn "Permanent:"
print $ permanent ms
main = do
let m1 = [[5]]
let m2 = [[1,0,0],[0,1,0],[0,0,1]]
let m3 = [[0,0,1],[0,1,0],[1,0,0]]
let m4 = [[4,3],[2,5]]
let m5 = [[2,5],[4,3]]
let m6 = [[4,4],[2,2]]
mapM_ result [m1,m2,m3,m4,m5,m6]