This is documentation for an old release of SciPy (version 0.10.1). Read this page Search for this page in the documentation of the latest stable release (version 1.15.1).

scipy.linalg.signm

scipy.linalg.signm(a, disp=True)

Matrix sign function.

Extension of the scalar sign(x) to matrices.

Parameters :

A : array, shape(M,M)

Matrix at which to evaluate the sign function

disp : boolean

Print warning if error in the result is estimated large instead of returning estimated error. (Default: True)

Returns :

sgnA : array, shape(M,M)

Value of the sign function at A

(if disp == False) :

errest : float

1-norm of the estimated error, ||err||_1 / ||A||_1

Examples

>>> from scipy.linalg import signm, eigvals
>>> a = [[1,2,3], [1,2,1], [1,1,1]]
>>> eigvals(a)
array([ 4.12488542+0.j, -0.76155718+0.j,  0.63667176+0.j])
>>> eigvals(signm(a))
array([-1.+0.j,  1.+0.j,  1.+0.j])