DATE     97/05/06

    Opérateur CFL                       voir aussi :TAILLE 
    --------------                                  CSON 
                                                      
                                                     
                                                          
     CHAM4  =  'CFL'  MODL1   |  MATR1   
                              |
                              |  ( CARA1 ) 'CSON' CHAM2  
                              |
                              |  MATR2  'TAILLE'  CHAM3 ;

    Description :
    _____________

     The CFL operator computes a lower bound of maximal stable
time step for each element associated with the Courant Friedriech 
Levy condition. Each element is considered free displacements 
boundary condition. There are two options to avoid computing either
the sound velocity or a geometric information. In such a case 
this last piece of information must be provided under the form
of a field by element ('CHAML' type object).

    Contents :
    __________


      MODL1 : the model ( MMODEL type object ).

      MATR1 : field by element ( MCHAML type object ) describing the
              material characteristics (operator MATE) of the model
              including the  geometrical parameter (operator CARA)
              such as  section, inertia ...


      MATR2 : field by element ( MCHAML type object ) describing the
              material characteristics (operator MATE) of the model

      CHAM2  : field by element ( MCHAML type object ) describing 
               sound velocity in each element. Its component name
               must be 'CSON'.

      CHAM3  : field by element ( MCHAML type object ) describing
               the maximum length for energy propagation between
               non adjacent nodes of the elements. Its component name
               must be 'L'  for massive element and an additional
               componenent 'L2H' for shells plate and beam elements

      CHAM4  : resulting field by element ( MCHAML type object )
               giving at the gravity center of each element the  
               time value 'TCFL'.

    Note :
    ______

     In order to determine a lower bound of the overall structure
time step, one may use the 'MINI' operator that gives the minimum 
of the field by element.