C
C----------------------------------------------------------------------
      SUBROUTINE CLUSTER4
C----------------------------------------------------------------------
C-
C-   Purpose and Methods : IT WORKS AS CLUSTER BUT USING TWO PARTS OF THE
C-   CALORIMETER (LAYERS 1 - 4 AND LAYERS 5 - 8) INSTEAD OF THE 8
C-   LAYERS .
C-
C-   Created   25-FEB-1995   MIRKO BOEZIO
C-   Modified  30-MAR-1995   MIRKO BOEZIO . CORRECTED AN ERROR IN THE
C-             DEFINITION OF THE TWO PARTS , OTHERWISE IT WAS LAYERS 1 - 5 AND
C-             LAYERS 6 - 8 .
C-
C----------------------------------------------------------------------
      INCLUDE 'INTEST.TXT'

      REAL QQQ(NCHA)
      COMMON / SHIFT / SHIFT
      SAVE / SHIFT /
C
      DO J = 1,4
        DO N = 1,2
          DO M = 1,NCHA
            CLUS4(N,J,M) = 0.
          ENDDO
          NCL4(N,J) = 0
        ENDDO
      ENDDO
C
      LPIANO = NPLA / 2
C
      DO N = 1,2
        DO J = 1,4
          DO M = 1,NCHA
            QQQ(M) = 0.
            DO L = 1,NPLA
              NLK = (M - 1) * NPLA + L
              EN = DEXY(N,L,M)
              IF (EN.GT.EMIN.AND.J.EQ.1.AND.L.LE.(LPIANO-6)) THEN
                QQQ(M) = QQQ(M) + EN
              ENDIF
              IF (EN.GT.EMIN.AND.J.EQ.2.AND.L.GT.(LPIANO-6).AND.L.LE.
     +             LPIANO) THEN
                QQQ(M) = QQQ(M) + EN
              ENDIF
             IF (EN.GT.EMIN.AND.J.EQ.3.AND.L.GT.LPIANO.AND.L.LE.
     +             (LPIANO+6)) THEN
                QQQ(M) = QQQ(M) + EN
              ENDIF
              IF (EN.GT.EMIN.AND.J.EQ.4.AND.L.GT.(LPIANO+6)) THEN
                QQQ(M) = QQQ(M) + EN
              ENDIF
           ENDDO
          ENDDO
C
          IGIRO = 0.
C
   50     CONTINUE
          MAX = LVMAX(QQQ,NCHA)
          IF (QQQ(MAX).LT.EMIN) GO TO 100
          MSTR = MAX
   55     CONTINUE
          MSTR = MSTR + 1
          IF (MSTR.GT.NCHA) GO TO 56
          IF (QQQ(MSTR).GT.EMIN) GO TO 55
   56     CONTINUE
          IB = MSTR - 1
C
          MSTR = MAX
   65     CONTINUE
          MSTR = MSTR - 1
          IF (MSTR.LT.1) GO TO 66
          IF (QQQ(MSTR).GT.EMIN) GO TO 65
   66     CONTINUE
          IA = MSTR + 1
C
          NN = 0
c          IF (M.EQ.2) NN = 1
c          IF (MOD(I,2).EQ.NN) THEN
          IF (MOD(J,2).EQ.NN) THEN
             IF (REVERSE.EQ.0) THEN
                SHIFT = -0.5
             ELSE
                SHIFT = +0.5
             ENDIF
          ELSE
             IF (REVERSE.EQ.0) THEN
                SHIFT = +0.5
             ELSE
                SHIFT = -0.5
             ENDIF          
          ENDIF
          CALL BARIC(QQQ,IA,IB,BAR,ENE,IERR1)
          IGIRO = IGIRO + 1
          IGI = IGIRO + NCHA / 2
          CLUS4(N,J,IGIRO) = BAR
          CLUS4(N,J,IGI) = ENE
C
          DO LL = IA,IB
            QQQ(LL) = 0.
          ENDDO
          GO TO 50
C
  100     CONTINUE
          NCL4(N,J) = IGIRO
        ENDDO
      ENDDO
C
      RETURN
      END