rithm of `T`

References
----------
.. [1] Awad H. Al-Mohy and Nicholas J. Higham (2012)
       "Improved Inverse Scaling and Squaring Algorithms
       for the Matrix Logarithm."
       SIAM Journal on Scientific Computing, 34 (4). C152-C169.
       ISSN 1095-7197

.. [2] Nicholas J. Higham (2008)
       "Functions of Matrices: Theory and Computation"
       ISBN 978-0-898716-46-7

.. [3] Nicholas J. Higham and Lijing lin (2011)
       "A Schur-Pade Algorithm for Fractional Powers of a Matrix."
       SIAM Journal on Matrix Analysis and Applications,
       32 (3). pp. 1056-1078. ISSN 0895-4798

r)