         (LDR,M*K) / (LDR,( N + M )*K)
          On input, the leading N*K-by-K part of R(K+1,1) /
          K-by-N*K part of R(1,K+1) contains the last block column /
          row of the previous Cholesky factor R.
          On exit, if INFO = 0, then the leading
          ( N + M )*K-by-M*K / M*K-by-( N + M )*K part of this
          array contains the last M*K columns / rows of the upper /
          lower Cholesky factor of T. The elements in the strictly
          lower / upper triangular part are not 