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scipy.linalg.

# signm

scipy.linalg.signm(A)

  Matrix sign function.

  Extension of the scalar sign(x) to matrices.

  The documentation is written assuming array arguments are of specified “core” shapes. However, array argument(s) of this function may have additional “batch” dimensions prepended to the core shape. In this case, the array is treated as a batch of lower-dimensional slices; see Batched Linear Operations for details. Note that calls with zero-size batches are unsupported and will raise a `ValueError`.

  Parameters:
    A(N, N) array_like

      Matrix at which to evaluate the sign function

  Returns:
    signm(N, N) ndarray

      Value of the sign function at A

  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])