each
                  step of reduction, and the "closest-neighbour"
                  strategy is used (see METHOD).

</PRE>
<B>Input/Output Parameters</B>
<PRE>
  N       (input) INTEGER
          The order of the matrices A, B, X and Y.  N &gt;= 0.

  PMAX    (input) DOUBLE PRECISION
          An upper bound for the "absolute value" of the elements of
          the individual transformations used for reduction
          (see METHOD and FURTHER COMMENTS).  PMAX &gt;= 1.0D0.

  A       (input/output) COMP