# [SciPy-dev] Missing functions --> Matrix functions, generalized eigenvalue problem, iterative solvers, CWT (Continuos wavelet transform)

Nils Wagner nwagner at mecha.uni-stuttgart.de
Wed Feb 27 11:44:25 CST 2002

Hi all,

The current output of
>>> help (linalg)

is

Linear algebra routines.

Solving Linear Systems:

inv        --- Find the inverse of a square matrix
solve      --- Solve a linear system of equations
det        --- determinant of a matrix
pinv       --- Moore-Penrose pseudo inverse (using least-squares)
pinv2      --- Moore-Penrose pseudo inverse (using SVD)
lstsq      --- Least-squares solve

Matrix Factorizations:

lu         --- LU decomposition
cholesky   --- Cholesky factorization
qr         --- QR factorization
schur      --- Schur decomposition
rsf2csf    --- Real to complex schur form.
norm       --- vector and matrix norm
eig        --- eigenvectors and eigenvalues
eigvals    --- only eigenvalues
svd        --- singular value decomposition

Matrix Functions

expm       --- exponential (using Pade approximation)
cosm       --- cosine
sinm       --- sine
tanm       --- tangent
coshm      --- hyperbolic cosine
sinhm      --- hyperbolic sine
tanhm      --- hyperbolic tangent
funm       --- arbitrary function

>>>
Is there any progress in implementing the matrix logarithm logm ?
Has anyone written some functions concerning the generalized eigenvalue
problem
(or even more general polynomial eigenvalue problems), that
is

A x = \lambda B x

(\lambda^n A_n + \dots + \lambda A_1 + A_0) x = 0

Are there any iterative solvers (CG, GMRES, ...) ?

Nils

I am also looking for discrete and continuous wavelet transforms.