Representación reducida de matrices dispersas

5 Comentarios

1. Haskell

   import Data.Matrix (Matrix, fromList, identity, zero, (!), nrows, ncols) reducida :: (Num a, Eq a) => Matrix a -> [[(Int,a)]] reducida p = [[(j,p!(i,j)) | j <- [1..ncols p], p!(i,j) /= 0] | i <- [1..nrows p]]

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   import Data.Matrix (Matrix, fromList, identity, zero, (!), nrows, ncols)   reducida :: (Num a, Eq a) => Matrix a -> [[(Int,a)]] reducida p =   [[(j,p!(i,j)) | j <- [1..ncols p], p!(i,j) /= 0] | i <- [1..nrows p]]

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2. Haskell

   import Data.Matrix reducida :: (Num a, Eq a) => Matrix a -> [[(Int,a)]] reducida p = map (borra0.zip [1..ncols p]) (toLists p) borra0 ::(Num a, Eq a) => [(Int,a)] -> [(Int,a)] borra0 [] = [] borra0 ((x,y):xs) | y == 0 = borra0 xs | otherwise = (x,y) : borra0 xs

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   import Data.Matrix   reducida :: (Num a, Eq a) => Matrix a -> [[(Int,a)]] reducida p =  map (borra0.zip [1..ncols p]) (toLists p)   borra0 ::(Num a, Eq a) => [(Int,a)] -> [(Int,a)] borra0 [] = [] borra0 ((x,y):xs) | y == 0 = borra0 xs                   | otherwise = (x,y) : borra0 xs

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   1. Haskell

      He llegado a una solución muy parecida, pero la he definido por comprensión. import qualified Data.Vector as V (toList) import Data.Matrix (Matrix, getRow, nrows, ncols) reducida :: (Num a, Eq a) => Matrix a -> [[(Int,a)]] reducida p = [borraCero (zip [1..ncols p] (V.toList (getRow i p))) | i <- [1..nrows p]] borraCero :: (Num a, Eq a) => [(Int,a)] -> [(Int,a)] borraCero [] = [] borraCero ((a,b):ps) | b == 0 = borraCero ps | otherwise = (a,b) : borraCero ps

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      He llegado a una solución muy parecida, pero la he definido por comprensión.   import qualified Data.Vector as V (toList) import Data.Matrix (Matrix, getRow, nrows, ncols)   reducida :: (Num a, Eq a) => Matrix a -> [[(Int,a)]] reducida p = [borraCero (zip [1..ncols p] (V.toList (getRow i p))) | i <- [1..nrows p]]   borraCero :: (Num a, Eq a) => [(Int,a)] -> [(Int,a)] borraCero [] = [] borraCero ((a,b):ps) | b == 0 = borraCero ps                      | otherwise = (a,b) : borraCero ps

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3. Haskell

   import Data.Matrix reducida :: (Num a, Eq a) => Matrix a -> [[(Int,a)]] reducida m = [[(j,a) | j<-[1..ncols m], let a = m ! (i,j), a /= 0] | i<-[1..nrows m]]

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   import Data.Matrix reducida :: (Num a, Eq a) => Matrix a -> [[(Int,a)]] reducida m = [[(j,a) | j<-[1..ncols m], let a = m ! (i,j), a /= 0] | i<-[1..nrows m]]

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4. Haskell

   import Data.Matrix reducida :: (Num a, Eq a) => Matrix a -> [[(Int,a)]] reducida = map aux . toLists where aux xs = [(i,x) | (i,x) <- zip [1..] xs, x /= 0]

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   import           Data.Matrix     reducida :: (Num a, Eq a) => Matrix a -> [[(Int,a)]] reducida = map aux . toLists   where     aux xs = [(i,x) | (i,x) <- zip [1..] xs, x /= 0]

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