def scale_matrix_numba(A, b):

    """ Scale a matrix A with a float.

    Parameters
    ----------
    A : array
        Base matrix.
    b : float
        Scalar value.

    Returns
    -------
    array
        Matrix A scaled by b.

    """

    for i in range(A.shape[0]):
        for j in range(A.shape[1]):
            A[i, j] *= b
    return A