Numeric.LinearAlgebra.Algorithms
 Portability uses ffi Stability provisional Maintainer Alberto Ruiz (aruiz at um dot es)
 Contents Linear Systems Matrix factorizations Singular value decomposition Eigensystems QR Cholesky Hessenberg Schur LU Matrix functions Nullspace Norms Misc Util
Description

A generic interface for some common functions. Using it we can write higher level algorithms and testing properties both for real and complex matrices.

In any case, the specific functions for particular base types can also be explicitly imported from Numeric.LinearAlgebra.LAPACK.

Synopsis
inv :: Field t => Matrix t -> Matrix t
pinv :: Field t => Matrix t -> Matrix t
pinvTol
det :: Field t => Matrix t -> t
rank :: Field t => Matrix t -> Int
rcond :: Field t => Matrix t -> Double
full :: Element t => (Matrix t -> (Matrix t, Vector Double, Matrix t)) -> Matrix t -> (Matrix t, Matrix Double, Matrix t)
economy :: Element t => (Matrix t -> (Matrix t, Vector Double, Matrix t)) -> Matrix t -> (Matrix t, Vector Double, Matrix t)
eigSH :: Field t => Matrix t -> (Vector Double, Matrix t)
chol :: Field t => Matrix t -> Matrix t
lu :: Field t => Matrix t -> (Matrix t, Matrix t, Matrix t, t)
expm :: Field t => Matrix t -> Matrix t
sqrtm :: Field t => Matrix t -> Matrix t
matFunc :: Field t => (Complex Double -> Complex Double) -> Matrix t -> Matrix (Complex Double)
nullspacePrec :: Field t => Double -> Matrix t -> [Vector t]
nullVector :: Field t => Matrix t -> Vector t
class Normed t where
 pnorm :: NormType -> t -> Double
data NormType
 = Infinity | PNorm1 | PNorm2
eps :: Double
i :: Complex Double
haussholder :: Field a => a -> Vector a -> Matrix a
unpackQR :: Field t => (Matrix t, Vector t) -> (Matrix t, Matrix t)
unpackHess :: Field t => (Matrix t -> (Matrix t, Vector t)) -> Matrix t -> (Matrix t, Matrix t)
class (Normed (Matrix t), Linear Matrix t) => Field t where
 svd :: Matrix t -> (Matrix t, Vector Double, Matrix t) linearSolve :: Matrix t -> Matrix t -> Matrix t linearSolveSVD :: Matrix t -> Matrix t -> Matrix t eig :: Matrix t -> (Vector (Complex Double), Matrix (Complex Double)) eigSH' :: Matrix t -> (Vector Double, Matrix t) cholSH :: Matrix t -> Matrix t qr :: Matrix t -> (Matrix t, Matrix t) hess :: Matrix t -> (Matrix t, Matrix t) schur :: Matrix t -> (Matrix t, Matrix t) ctrans :: Matrix t -> Matrix t
Linear Systems
 inv :: Field t => Matrix t -> Matrix t Source
Inverse of a square matrix using lapacks' dgesv and zgesv.
 pinv :: Field t => Matrix t -> Matrix t Source
Pseudoinverse of a general matrix using lapack's dgelss or zgelss.
pinvTol
 det :: Field t => Matrix t -> t Source
determinant of a square matrix, computed from the LU decomposition.
 rank :: Field t => Matrix t -> Int Source
Number of linearly independent rows or columns.
 rcond :: Field t => Matrix t -> Double Source
Reciprocal of the 2-norm condition number of a matrix, computed from the SVD.
Matrix factorizations
Singular value decomposition
 full :: Element t => (Matrix t -> (Matrix t, Vector Double, Matrix t)) -> Matrix t -> (Matrix t, Matrix Double, Matrix t) Source

A version of svd which returns an appropriate diagonal matrix with the singular values.

If (u,d,v) = full svd m then m == u <> d <> trans v.

 economy :: Element t => (Matrix t -> (Matrix t, Vector Double, Matrix t)) -> Matrix t -> (Matrix t, Vector Double, Matrix t) Source

A version of svd which returns only the nonzero singular values and the corresponding rows and columns of the rotations.

If (u,s,v) = economy svd m then m == u <> diag s <> trans v.

Eigensystems
 eigSH :: Field t => Matrix t -> (Vector Double, Matrix t) Source

Eigenvalues and Eigenvectors of a complex hermitian or real symmetric matrix using lapack's dsyev or zheev.

If (s,v) = eigSH m then m == v <> diag s <> ctrans v

QR
Cholesky
 chol :: Field t => Matrix t -> Matrix t Source

Cholesky factorization of a positive definite hermitian or symmetric matrix using lapack's dpotrf or zportrf.

If c = chol m then m == c <> ctrans c.

Hessenberg
Schur
LU
 lu :: Field t => Matrix t -> (Matrix t, Matrix t, Matrix t, t) Source

LU factorization of a general matrix using lapack's dgetrf or zgetrf.

If (l,u,p,s) = lu m then m == p <> l <> u, where l is lower triangular, u is upper triangular, p is a permutation matrix and s is the signature of the permutation.

Matrix functions
 expm :: Field t => Matrix t -> Matrix t Source
Matrix exponential. It uses a direct translation of Algorithm 11.3.1 in Golub & Van Loan, based on a scaled Pade approximation.
 sqrtm :: Field t => Matrix t -> Matrix t Source

Matrix square root. Currently it uses a simple iterative algorithm described in Wikipedia. It only works with invertible matrices that have a real solution. For diagonalizable matrices you can try matFunc sqrt.

```m = (2><2) [4,9
,0,4] :: Matrix Double```
```>sqrtm m
(2><2)
[ 2.0, 2.25
, 0.0,  2.0 ]```
 matFunc :: Field t => (Complex Double -> Complex Double) -> Matrix t -> Matrix (Complex Double) Source

Generic matrix functions for diagonalizable matrices. For instance:

`logm = matFunc log`
Nullspace
 nullspacePrec Source
 :: Field t => Double relative tolerance in eps units -> Matrix t input matrix -> [Vector t] list of unitary vectors spanning the nullspace The nullspace of a matrix from its SVD decomposition.
 nullVector :: Field t => Matrix t -> Vector t Source
The nullspace of a matrix, assumed to be one-dimensional, with default tolerance (shortcut for last . nullspacePrec 1).
Norms
 class Normed t where Source

Objects which have a p-norm. Using it you can define convenient shortcuts:

`norm2 x = pnorm PNorm2 x`
`frobenius m = norm2 . flatten \$ m`
Methods
 pnorm :: NormType -> t -> Double Source Instances
 Normed (Vector Double) Normed (Vector (Complex Double)) Normed (Matrix Double) Normed (Matrix (Complex Double))
 data NormType Source
Constructors
 Infinity PNorm1 PNorm2
Misc
 eps :: Double Source
The machine precision of a Double: eps = 2.22044604925031e-16 (the value used by GNU-Octave).
 i :: Complex Double Source
The imaginary unit: i = 0.0 :+ 1.0
Util
 haussholder :: Field a => a -> Vector a -> Matrix a Source
 unpackQR :: Field t => (Matrix t, Vector t) -> (Matrix t, Matrix t) Source
 unpackHess :: Field t => (Matrix t -> (Matrix t, Vector t)) -> Matrix t -> (Matrix t, Matrix t) Source
 class (Normed (Matrix t), Linear Matrix t) => Field t where Source
Auxiliary typeclass used to define generic computations for both real and complex matrices.
Methods
 svd :: Matrix t -> (Matrix t, Vector Double, Matrix t) Source
Singular value decomposition using lapack's dgesvd or zgesvd.
 linearSolve :: Matrix t -> Matrix t -> Matrix t Source
Solution of a general linear system (for several right-hand sides) using lapacks' dgesv and zgesv. See also other versions of linearSolve in Numeric.LinearAlgebra.LAPACK.
 linearSolveSVD :: Matrix t -> Matrix t -> Matrix t Source
 eig :: Matrix t -> (Vector (Complex Double), Matrix (Complex Double)) Source

Eigenvalues and eigenvectors of a general square matrix using lapack's dgeev or zgeev.

If (s,v) = eig m then m <> v == v <> diag s

 eigSH' :: Matrix t -> (Vector Double, Matrix t) Source
Similar to eigSH without checking that the input matrix is hermitian or symmetric.
 cholSH :: Matrix t -> Matrix t Source
Similar to chol without checking that the input matrix is hermitian or symmetric.
 qr :: Matrix t -> (Matrix t, Matrix t) Source

QR factorization using lapack's dgeqr2 or zgeqr2.

If (q,r) = qr m then m == q <> r, where q is unitary and r is upper triangular.

 hess :: Matrix t -> (Matrix t, Matrix t) Source

Hessenberg factorization using lapack's dgehrd or zgehrd.

If (p,h) = hess m then m == p <> h <> ctrans p, where p is unitary and h is in upper Hessenberg form.

 schur :: Matrix t -> (Matrix t, Matrix t) Source

Schur factorization using lapack's dgees or zgees.

If (u,s) = schur m then m == u <> s <> ctrans u, where u is unitary and s is a Shur matrix. A complex Schur matrix is upper triangular. A real Schur matrix is upper triangular in 2x2 blocks.

"Anything that the Jordan decomposition can do, the Schur decomposition can do better!" (Van Loan)

 ctrans :: Matrix t -> Matrix t Source
Conjugate transpose. Instances
 Field Double Field (Complex Double)