subroutine mtran (n, A)
c
      double precision A(n,1)
      integer n
c    ***----------------------------------------------------------***
c    *   'mtran' overwrites A with transpose(A).                    *
c    *                                                              *
c    *    on entry                                                  *
c    *                                                              *
c    *           n [integer]                                        *
c    *             The number of rows and columns in A.             *
c    *             (If A is dimensioned as a 2D array in            *
c    *             the calling (sub) program, n must be the         *
c    *             leading dimension.)                              *
c    *                                                              *
c    *           A [double precision(n,n)]                          *
c    *             The matrix to be transposed.                     *
c    *                                                              *
c    *   on return                                                  *
c    *                                                              *
c    *           n [integer]                                        *
c    *             Unchanged.                                       *
c    *                                                              *
c    *           A [double precision(n,n)]                          *
c    *             The transpose of A.                              *
c    ***----------------------------------------------------------***
         double precision temp
         integer i, j
c
         do 20 j = 1, n
            do 10 i = j+1, n
               temp = A(i,j)
               A(i,j) = A(j,i)
               A(j,i) = temp
  10        continue
  20     continue
      return
      end