MODULE Funkt
      CONTAINS
       FUNCTION RAND (m)
        INTEGER m
        REAL, DIMENSION(m,m,m) :: RAND
         CALL RANDOM_NUMBER(HARVEST = RAND)
        RETURN
       END FUNCTION RAND
      END MODULE Funkt

      PROGRAM TRANSITION
      USE Funkt
      IMPLICIT NONE
       INTEGER, PARAMETER :: n = 16
       INTEGER            :: iterations, i
       LOGICAL, DIMENSION(n,n,n) :: ising,     flips
       INTEGER, DIMENSION(n,n,n) :: ones,      count
       REAL, DIMENSION(n,n,n)    :: threshold
       REAL, DIMENSION(6)        :: p

       p = (/ 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 /)

       iterations  = 10
       ising = RAND(n) .LE. 0.5

       DO i = 1,iterations
        ones = 0
        WHERE (ising) ones = 1
        count = CSHIFT(ones, -1, 1) + CSHIFT(ones, 1, 1) &
              + CSHIFT(ones, -1, 2) + CSHIFT(ones, 1, 2) &
              + CSHIFT(ones, -1, 3) + CSHIFT(ones, 1, 3)
        WHERE (.NOT.ising) count = 6 - count
        threshold = 1.0
        WHERE (count == 4) threshold = p(4)
        WHERE (count == 5) threshold = p(5)
        WHERE (count == 6) threshold = p(6)
        flips = RAND(n) .LE. threshold
        WHERE (flips) ising = .NOT. ising
       ENDDO
      END PROGRAM TRANSITION