C ------ CUBEEXCH.F77 ------------------------------------ 26.03.91 -----
C                                                        (c) M.Pester 
C -------------------------------------------------------- 31.03.92 -----
C --- CUBE_EXCH: Distribute N words from each process to each other
C                (GLOBAL EXCHANGE ALGORITHM)
C                sort by the process number IP
C
      SUBROUTINE CUBE_EXCH(N,WORDS,Y,IP)
C --    Input : N, WORDS(N), IProcessor (sorting)
C --    Output: Y(N,Nproc)
        INCLUDE 'include/trnet.inc'
      DIMENSION  WORDS(N), Y(1)
      NT=N
      NR=IP
      IS=IP*N+1
      CALL VIcopy(N,Y(IS),1,WORDS,1)
      DO 10 L=1,NCUBE
        IS=NR*NT+1
        IR=IEOR(NR,1)*NT+1
        CALL EXCHNG(L,NT,Y(IS),Y(IR))
        NT=ISHFT(NT, 1)
        NR=ISHFT(NR,-1)
10    CONTINUE
      RETURN
      END