SUBROUTINE  voisinage(  nbdims,  dims,  coords,  periods,  voisin  )
      USE numerics
      INTEGER,                        INTENT(IN)   ::  nbdims
      INTEGER,  DIMENSION(1:nbdims),  INTENT(IN)   ::  dims
      INTEGER,  DIMENSION(1:nbdims),  INTENT(IN)   ::  coords
      LOGICAL,  DIMENSION(1:nbdims),  INTENT(IN)   ::  periods
      INTEGER,  PARAMETER              ::  NB_VOISINS  =  6
      INTEGER,  DIMENSION(NB_VOISINS),  INTENT(OUT)  ::  voisin
      END  SUBROUTINE  voisinage