numidr/src/Data/NumIdr/Matrix.idr

104 lines
2.5 KiB
Idris

module Data.NumIdr.Matrix
import Data.Vect
import Data.NumIdr.Multiply
import public Data.NumIdr.Array
import Data.NumIdr.Vector
%default total
public export
Matrix : Nat -> Nat -> Type -> Type
Matrix m n = Array [m,n]
public export
Matrix' : Nat -> Type -> Type
Matrix' n = Matrix n n
--------------------------------------------------------------------------------
-- Matrix constructors
--------------------------------------------------------------------------------
export
matrix' : {m, n : _} -> Order -> Vect m (Vect n a) -> Matrix m n a
matrix' ord x = array' [m,n] ord x
export
matrix : {m, n : _} -> Vect m (Vect n a) -> Matrix m n a
matrix = matrix' COrder
export
repeatDiag : {m, n : _} -> (diag, other : a) -> Matrix m n a
repeatDiag d o = fromFunction [m,n]
(\[i,j] => if i `eq` j then d else o)
where
eq : {0 m,n : Nat} -> Fin m -> Fin n -> Bool
eq FZ FZ = True
eq (FS x) (FS y) = eq x y
eq FZ (FS _) = False
eq (FS _) FZ = False
export
fromDiag : {m, n : _} -> (diag : Vect (minimum m n) a) -> (other : a) -> Matrix m n a
fromDiag ds o = fromFunction [m,n] (\[i,j] => maybe o (`index` ds) $ i `eq` j)
where
eq : {0 m,n : Nat} -> Fin m -> Fin n -> Maybe (Fin (minimum m n))
eq FZ FZ = Just FZ
eq (FS x) (FS y) = map FS (eq x y)
eq FZ (FS _) = Nothing
eq (FS _) FZ = Nothing
export
identity : Num a => {n : _} -> Matrix n n a
identity = repeatDiag 1 0
export
scaling : Num a => {n : _} -> a -> Matrix n n a
scaling x = repeatDiag x 0
export
rotation2D : Double -> Matrix' 2 Double
rotation2D a = matrix [[cos a, - sin a], [sin a, cos a]]
--------------------------------------------------------------------------------
-- Indexing
--------------------------------------------------------------------------------
export
index : Fin m -> Fin n -> Matrix m n a -> a
index m n = index [m,n]
export
indexMaybe : Nat -> Nat -> Matrix m n a -> Maybe a
indexMaybe m n = indexMaybe [m,n]
export
getRow : Fin m -> Matrix m n a -> Vector n a
getRow r mat = rewrite sym (minusZeroRight n) in indexRange [One r, All] mat
export
getColumn : Fin n -> Matrix m n a -> Vector m a
getColumn c mat = rewrite sym (minusZeroRight m) in indexRange [All, One c] mat
--------------------------------------------------------------------------------
-- Operations
--------------------------------------------------------------------------------
export
vconcat : Matrix m n a -> Matrix m' n a -> Matrix (m + m') n a
vconcat = concat 0
export
hconcat : Matrix m n a -> Matrix m n' a -> Matrix m (n + n') a
hconcat = concat 1