Operator CHI2
                                             DATE     97/12/30
  
   Opérateur CHI2
   --------------
       TAB4 = CHI2  TAB1  TAB2  <TAB3> ;

     Description :
     -------------
     The CHI1 and CHI2 operators allow the calculation of chemical
     equilibria in aqueous systems.The terminology is the one of MINEQL.

      All the concentrations are in Mole/Liter

     Contents:
     ---------

       TAB1 is a TABLE type object, subtype CHIMI1. (cf operator CHI1)

       TAB2 is a TABLE type object, subtype 'DONNEES_CHIMIQUES'.
            Its indices are the words :
           'LOGC' 'TOT' <'FIONI'> <'NTY4'> <'TEMPE'>  <'CLIM'>

       TAB2.LOGC is a CHPOIN type object. Contains a component for each
             chemical component. For each chemical component contains 
             the log of the concentration of species.
             The name of the components of CHPOIN is a word of 4 
             characters, which contains X followed, if necessary, by 0 
             or 00 and the identification number of chemical component.

       TAB2.TOT is a CHPOIN type object. Contains a component for each
             chemical component. For each chemical component contains 
             the analytical (total) concentration.
             The name of the components of CHPOIN is a word of 4 
             characters, which contains X followed, if necessary, by 0 
             or 00 and the identification number of chemical component.

       TAB2.FIONI is a CHPOIN type object. Scalar at nodes. Contains a
             initial value of ionic strength.

       TAB2.NTY4 is a CHPOIN type object. Contains a component for each
             dissolved solids which are subject to precipitation.
             In each node of mesh contains 1 for precipitated solid and
             0 for dissolved solid. The CHPOIN components names are in 
             the list of TAB1.IDEN.NOMPRECI.

       TAB2.TEMPE is a CHPOIN type object. The temperature.

       TAB2.CLIM is a CHPOIN type object. The fixed activity  for type 3
             species. The CHPOIN components names are in the list 
             TAB1.IDEN.NOMTYP3.

       TAB3 is a TABLE type object. Contains the parameters.
            Its indices are the words :
            <'EPS'> <'ITMAX'> <'ITERSOLI'> <'PRECPE'> <'IAFFICHE'>
            <'NITERPE'> <'DELPE'> <'MDELPE'> <'NFI'>  <'SORTIE'>
            <'IMPRIM'>

       TAB3.EPS is a real. The tolerance in the convergence test. The
             default value is 1.E-4

       TAB3.ITMAX   is an integer. The maximum number of iterations
             allowed to solve the chemical system. Default value 20.

       TAB3.ITERSOLI is an integer. The maximum number of iterations
             allowed to find precipitate minerals. Default value 10.

       TAB3.IAFFICHE is an integer allowing the display of results
             choice for solid-solution.
             1  solid-solution stoichiometric coefficients
             2  solid-solution mole fractions
             Default value 2.

       TAB3.PRECPE is a real. Convergence criterion in calculation of
             redox. Default value 1.E-10

       TAB3.NITERPE  is an integer. The maximum number of iterations
              allowed for dichotomy. Default value 50.

       TAB3.DELPE is a real. Initial interval for dichotomy iterations.
               Default value 1.

       TAB3.MDELPE  (integer). The maximum  number of steps in the
          search of dichotomy space.Default value 20.

       TAB3.NFI is an integer.The number of chemistry cycles. Default
              value 4. A cycle corresponds to the sequence:
                       * ionic strength computation
                       * modification of logk
                                              |---
                       * loop for precipitate |* iterative solution of
                            minerals          |  the system
                                              |
                                              |* Verification of
                                              |  precipitated minerals.
                                              |---

       TAB2.SORTIE is a LISTMOTS type object. These words are included
             in the list of words:
             'PREC' 'FION' 'TYP6' 'TYP3' 'NTY4' 'TYP5' 'SURF' 'SOLU'
             'POLE' 'LOGK'
             These words are used to specify the indices of TABLE TAB4.

       TAB2.IMPRIM is a LISTENTI type object. When the message level is
             greater than 0  ( OPTION IMPI 1 ), prints for the nodes of
             list only.




       TAB4 is a TABLE type object, subtype CHIMI2. Its indices are the
            words:
           'AQUE' 'FIXE' 'LOGC' <'PREC'>  <'FION'> <'TYP6'> <'TYP3'>
             <'NTY4'> <'TYP5'> <'SURF'> <'SOLU'> <'POLE'> <'LOGK'>

       TAB4.AQUE is a CHPOIN type object. Contains a component for each
             chemical component. Contains the component concentration in 
             solution. The name of the component of CHPOIN is a word of
             4 characters, which contains X followed, if necessary, by 0
             or 00 and the identification number of chemical component.

       TAB4.FIXE is a CHPOIN type object. Contains a component for each
             chemical component. Contains the component concentration of
             solids ( precipitated+surface).

       TAB4.LOGC is a CHPOIN type object. Contains a component for each
             chemical component. For each chemical component contains 
             the log of the concentration of species.

       TAB4.PREC  is a CHPOIN type object. Contains a component for each
              precipitated species. Contains the precipitated species
              concentrations. The CHPOIN components names are in the
              list TAB1.IDEN.NOMPRECI.

       TAB4.FION is a CHPOIN type object.Contains the value of ionic
             strength.

       TAB4.TYP6 is a CHPOIN type object. Contains a component for each
             type 6 chemical species. The CHPOIN components names are in
             the list TAB1.IDEN.NOMTYP6. Contains the concentration of
             type 6 species ( species which are not to be considered).

       TAB4.TYP3 is a CHPOIN type object. Contains a component for each
             type 3 chemical species. The CHPOIN components names are in
             the list TAB1.IDEN.NOMTYP3. Contains the concentration of
             type 3 species.(fixed species concentration)

       TAB4.NTY4 is a CHPOIN type object. Contains a component for each
             solids which are subject to precipitation.
             In each node of mesh contains 1 for precipitated solid and 
             0 for dissolved solid. The CHPOIN components names are in 
             the list of TAB1.IDEN.NOMPRECI.

       TAB4.TYP5 is a CHPOIN type object. Contains a component for each
             type 5 chemical species. Contains the concentration of type
             5 species. Type 5 species are dissolved solids which are
             subject to precipitation if the solubility product is 
             exceeded.

       TAB4.SURF is a CHPOIN type object. Contains a component for each
              surface chemical species. Contains the concentration of
              surfaces species.

       TAB4.SOLU is a CHPOIN type object. Contains a component for each
             dissolved species.Contains the concentration of dissolved
             species.

       TAB4.POLE is a CHPOIN type object. Contains a component for each
             solid-solution pure endmember. Contains the solid-solution
             pure endmember mole fractions. The CHPOIN components names 
             are in the list TAB1.IDEN.NOMPOLE.

       TAB4.LOGK is a CHPOIN type object. Contains a component for each
             solid-solution. Contains the logK of the solid-solution. The 
             CHPOIN components names are in the list TAB1.IDEN.NOMSOSO.