# scipy.linalg.signm

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

  Matrix sign function.

  Extension of the scalar sign(x) to matrices.

  Parameters:
    A(N, N) array_like

      Matrix at which to evaluate the sign function

    disp bool, optional

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

  Returns:
    signm(N, N) ndarray

      Value of the sign function at A

    errest float

      (if disp == False)

      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])