 (input/output) DOUBLE PRECISION array, dimension (LDA,N)
          On entry, the leading N-by-N part of this array must
          contain the state dynamics matrix of the original system.
          On exit, the leading NR-by-NR part of this array contains
          the state dynamics matrix Ar of the reduced order system.

  LDA     INTEGER
          The leading dimension of array A.  LDA &gt;= MAX(1,N).

  B       (input/output) DOUBLE PRECISION array, dimension (LDB,M)
          On entry, the leading N-b