Module « scipy.linalg »

Fonction sqrtm - module scipy.linalg

Signature de la fonction sqrtm

def sqrtm(A, disp=True, blocksize=64) 

Description

sqrtm.__doc__

    Matrix square root.

    Parameters
    ----------
    A : (N, N) array_like
        Matrix whose square root to evaluate
    disp : bool, optional
        Print warning if error in the result is estimated large
        instead of returning estimated error. (Default: True)
    blocksize : integer, optional
        If the blocksize is not degenerate with respect to the
        size of the input array, then use a blocked algorithm. (Default: 64)

    Returns
    -------
    sqrtm : (N, N) ndarray
        Value of the sqrt function at `A`

    errest : float
        (if disp == False)

        Frobenius norm of the estimated error, ||err||_F / ||A||_F

    References
    ----------
    .. [1] Edvin Deadman, Nicholas J. Higham, Rui Ralha (2013)
           "Blocked Schur Algorithms for Computing the Matrix Square Root,
           Lecture Notes in Computer Science, 7782. pp. 171-182.

    Examples
    --------
    >>> from scipy.linalg import sqrtm
    >>> a = np.array([[1.0, 3.0], [1.0, 4.0]])
    >>> r = sqrtm(a)
    >>> r
    array([[ 0.75592895,  1.13389342],
           [ 0.37796447,  1.88982237]])
    >>> r.dot(r)
    array([[ 1.,  3.],
           [ 1.,  4.]])