C   THIS SUBROUTINE SORTS ANY SPECIFIED PART OF THE A ARRAY. INCLUSIVE
C   LIMITS FOR THIS SORT ARE THE UPPER AND LOWER INDICES IL,AND IU.
C   A SIMPLE PERMUTATION SORT IS USED.
C
      SUBROUTINE PERMUT (A,N,IL,IU)
      DIMENSION A(N)
      MM=IU-1
      DO 20 I=IL,MM
      II=I+1
      JHOLD=I
      DO 10 J=II,IU
      IF (A(JHOLD).LE.A(J)) GO TO 10
      JHOLD=J
   10 CONTINUE
      IF (JHOLD.EQ.I) GO TO 20
      Q=A(I)
      A(I)=A(JHOLD)
      A(JHOLD)=Q
   20 CONTINUE
      RETURN
      END