       (W is not returned).</pre><p>
<pre>   X      (input/output) FLOAT PRECISION array, dimension (N)   
          On an intermediate return, X should be overwritten by   
                A * X,   if KASE=1,   
                A' * X,  if KASE=2,
         and SLACON must be re-called with all the other parameters   
          unchanged.</pre><p>
<pre>   ISGN   (workspace) INT array, dimension (N)</pre><p>
<pre>   EST    (output) FLOAT PRECISION   
          An estimate (a lower bound) for norm(A).</pre><p