def add_mult_sign(self, mat2, mult = 1.):
    """
    Add multiple of sign of mat2 to the matrix.
    """

    err_code = _eigenmat.add_mult_sign(self.p_mat, mat2.p_mat, ct.c_float(mult))
    if err_code:
      raise generate_exception(err_code)

    return self

    Add multiple of sign of mat2 to the matrix.
    
eigenmat/eigenmat.py