subroutine mnegv (n, A)
c
      double precision A(1)
      integer n
c    ***----------------------------------------------------------***
c    *   'mnegv' overwrites A with -A.                              *
c    *                                                              *
c    *    on entry                                                  *
c    *                                                              *
c    *           n [integer]                                        *
c    *             The (implicit) number of rows and columns        *
c    *             in A.  A is accessed as a 1D array inside        *
c    *             this subroutine.                                 *
c    *                                                              *
c    *           A [double precision(n**2)]                         *
c    *             The matrix to be negated.                        *
c    *                                                              *
c    *   on return                                                  *
c    *                                                              *
c    *           n [integer]                                        *
c    *             Unchanged.                                       *
c    *                                                              *
c    *           A [double precision(n**2)]                         *
c    *             Overwritten with -A.                             *
c    ***----------------------------------------------------------***
         integer k, nsquar
c
         nsquar = n**2
         do 10 k = 1, nsquar
            A(k) = - A(k)
  10     continue
      return
      end