%N hsortr %F $MIR/src/subs/hsort.for
%D Perform an indexed heapsort on a real array.
%P jm
%: sorting
%B
      subroutine hsortr(n, array, indx)

      implicit none
      integer n, indx(n)
      real array(n)

  HSORTR performs an index based heapsort on a real array.
  The number of elements in the array and the array are left unchanged.
  The size of the indx array should be at least as large as the size of
  the real array.

     Input:
       n        The number of elements in the array.
       array    The real array on which to base the sort.

     Output:
       indx     Sorted integer index array such that array(indx(1)) is
                the smallest and array(indx(n)) is the largest element.
