SHTOOLS --- Tools for working with spherical harmonics

> Home > Documentation > Python > Other

EigValSym

Compute the eigenvalues of a real symmetric matrix.

Usage

eval = pyshtools.EigValSym (ain, [n, ul])

Returns

eval : float, dimension (n)
The eigenvalues of ain, sorted from largest to smallest.

Parameters

ain : float, dimension (nin, nin)
The input real symmetric matrix. By default, only the upper portion of the matrix is used.
n : optional, integer, default = nin
The rank of the matrix ain.
ul : optional, character, default = U
If U then the upper portion of the matrix ain will be used (default). If L then the lower portion of the matrix ain will be used.

Description

EigValSym will calculate the eigenvalues of a real symmetric matrix. By default, only the upper portion of the matrix is used, but this can be changed by the optional argument ul. The eigenvalues are sorted from largest to smallest. The matrix ain is first factorized into a tridiagonal matrix using the LAPACK routine DSYTRD, and then the eigenvalues are calculated by a call to DSTEGR.

See also

eigvalvecsym, eigvalvecsymtri

> Home > Documentation > Python > Other

Institut de Physique du Globe de Paris University of Sorbonne Paris Cité © 2016 SHTOOLS