be the identity matrix
          and is not referenced.
          On exit, if EQUIL = 'S' and CKPROP = 'N', the leading
          K-by-K part of this array contains the descriptor matrix
          of an equivalent, scaled system.
          On exit, if CKPROP = 'C', DICO = 'C', and JOBE &lt;&gt; 'I', the
          leading MIN(K,NR)-by-MIN(K,NR) part of this array contains
          the descriptor matrix of an equivalent reduced, possibly
          scaled (if EQUIL = 'S') system, used to check the
          p