C-----------------------------------------------------------------------
C  Get the lattice mode of the conventional cell
C-----------------------------------------------------------------------
      SUBROUTINE LATMOD (LAT,MODE)
      REAL LAT
      DIMENSION LAT(3,3),M(3)
      CHARACTER*1 CMODE
      CALL MATRIX(LAT(1,1),LAT(1,2),LAT(1,3),DET,'DETERM')
      IDET = ABS(DET) + .1
      CMODE = ' '
      IF (IDET .EQ. 1) CMODE = 'P'
      IF (IDET .EQ. 3) CMODE = 'R'
      IF (IDET .EQ. 4) CMODE = 'F'
      IF (IDET .NE. 2) GO TO 130
        DO 120 I = 1,2
        M(1) = MOD(I,2)
          DO 120 J = 1,2
          M(2) = MOD(J,2)
            DO 120 K = 1,2
            M(3) = MOD(K,2)
            IF (M(1) + M(2) + M(3) .LT. 2) GO TO 120
              DO 110 L = 1,3
              ISUM = 0
                DO 100 N = 1,3
  100           ISUM = ISUM + M(N)*ABS(LAT(L,N)) + 0.1
              IF (MOD(ISUM,2) .NE. 0) GO TO 120
  110         CONTINUE
            CMODE = 'I'
            IF (M(1) .EQ. 0) CMODE = 'A'
            IF (M(2) .EQ. 0) CMODE = 'B'
            IF (M(3) .EQ. 0) CMODE = 'C'
            GO TO 130
  120       CONTINUE
  130 READ (CMODE,10000) MODE
      RETURN
10000 FORMAT (A1)
      END