integer parent,xkey,ikey
      xkey = a(jkey)
      ikey = ind(jkey)
c      node = node + 1
      a(node) = xkey
      ind(node) = ikey
      rind(ikey) = node
      if (node .le. 1) return
      child=node
 1    parent = child/2
      if (a(parent) .le. a(child)) goto 2
      call interchange(a,ind,rind,child,parent)
      child = parent
      if (child .gt. 1) goto 1
 2    continue
      return
      end