this array must contain,
          in the first K-by-K block of the second block row /
          column, the lower right block of the Cholesky factor of
          the inverse of T, and in the remaining part, the generator
          of the inverse of T.
          On exit, if INFO = 0 and JOB = 'R', or 'A', then the
          leading 2*K-by-( N + M )*K / ( N + M )*K-by-2*K part of
          this array contains the same information as on entry, now
          for the updated Toeplitz matrix. Actually, to obtain