    -----  date of latest change: oct.  7, '82  -----
 QUESTION:
 Invoke larkin subsystem:
 EDIT / COMPILE / SIMULATE / NUMERICAL OUTPUT / PLOT / QUIT / ?

 General remarks:
 The package  L A R K I N  consists of the above mentioned subsystems.
 To perform an entire simulation of a chemical model the standard
 procedure is as follows:
 1.) set up a new problem ( or modify a model stored on database
     'CHEMIN' ) using the subsystem EDIT.
 2.) compilation of the actual problem (stored on 'CHEMIN') from
     chemical input language to a package oriented form by subsystem
     COMPILE.
 3.) perform the real simulation by subsystem SIMULA (the output of the
     last COMPILE-run, stored on database 'INVAL', is used as input)
 4.) output of simulation data by subsystem NUMERICAL OUTPUT (lists
     data in numerical form) and/or by subsystem PLOT (output of data
     in graphical form). As input, the output of the last SIMULA-run,
     stored on database 'OUT', is used.


 ANSWERS:
 General remark:
 In the whole package the leading letter of a possible answer is
 sufficient as reply. Optional following numbers has to be seperated
 by blanks.

 -EDIT:
    modify actual model or enter a complete new model
    (a currently stored model is overwritten)
 -COMPILE (I1):
    invokes the chemical compiler to interprete the chemical input
    (stored on database 'CHEMIN'). I1 is an (optional) integer number
    used to overwrite (temporary) the internal standard print flag.
    I1 = 0:  only error messages are written (on terminal)
       = 1:  error and warning messages are written (on terminal)
             this is the standard value (used if no I1 is entered)
       = 2:  error, warnings and compiler input listing (on terminal)

       = 10/11/12:  as 0/1/2 but written on printer

 -SIMULATE (I1):
    performs the simulation of the chemical reaction system by
    integration of the associated ODE-system (stored on database
    'INVAL')
    I1 = 0:  error messages of the integrator are written (on terminal)
       = 1:  integration monitor
             (internal standard value)
       = 2:  enhanced integration monitor
       = 10/11/12:  as 0/1/2 but written on printer

 -NUMERICAL OUTPUT (I1):
    performs the listing of the available simulation data (stored on
    database 'OUT')
    I1 = 0:  a fixed standard output listing is written (on terminal)
             ( no dialog facility )
       = 1:  selection of output data by dialog facility
             (internal standard value)
       = 10/11:  as 0/1 but written on printer


 QUESTION:
 work with input data:
 / NEW / MODIFY / LIST / PRINT / QUIT / ?

 ANSWERS:
 -NEW:    deletes whole current input data and prepares the input
          database 'CHEMIN' for subsequent modifications to set up the
          new model
 -MODIFY: modify current input data (-> add,change,delete)
 -LIST:   lists whole actual input data of larkin
 -PRINT:  makes hardcopy of actual input data of LARKIN
 -QUIT:   leaves subsystem EDIT of LARKIN


 QUESTION:
 Modify:
 / HEAD / ELEMENT LIST / SPECIES LIST / CHEMICAL EQUATIONS /
 / INITIAL CONCENTRATIONS / TEMPERATURE / GAS CONSTANT /
 / NUMERICAL INPUT / QUIT / RETURN / ?

 (indication, which part of current input data should be modified)

 ANSWERS:
 -HEAD: a head for indication of current model (up to 5 lines of text)
 -ELEMENT LIST:  a list of element names, which may be used for the
                 definition of species composition. Each element may be
                 followed by its atomic weight (seperated by blank).
                 ( enter one element per line)
 -SPECIES LIST:  a list of the species names, which are used in the
                 chemical reaction system. Their place in this list
                 defines their number in the ODE-system. Each species
                 may be followed by its element composition (seperated
                 by blanks).
                 ( enter one element per line)
 -CHEMICAL EQUATION:  a set of chemical reaction equations
 -INITIAL CONCENTRATIONS:  values for non-zero concentration at the
                           starting point of integration (simulation)
 -TEMPERATURE: ( if ARRHENIUS law is used for kinetic parameters)
 -GAS CONSTANT: ( if ARRHENIUS law is used for kinetic parameters)
                ( enter TEMPERATURE, GAS CONSTANT and INITIAL CONC.
                  in same units )
 -NUMERICAL INPUT:  (eps, iprint, start-(t), final-(t) or out-(t))
 -QUIT:  leaves this question level
 -RETURN:  leaves subsystem EDIT


 QUESTION:
 modify 'current input':
 / LIST / ADD / CHANGE / DELETE / QUIT / RETURN / ?
 'current input' means: either head, element list, species list,
                               chemical equations or initial concentr.

 ANSWERS:
 (the numbers I1 and I2 are optional;they have to be seperated by blanks

 -LIST:       lists whole current data lines
 -LIST I1:    lists lines 1 to I1 of current data
 -LIST I1 I2: lists lines I1 to I2

 -ADD:       allows to add new line(s) under the last input line of
             current part
 -ADD I1:    the new line(s) are inserted under line I1

 -CHANGE:    allows to change a line of current input part
             in parts 'head' and 'chemical equations' EDIT asks then for
             the line number to be changed;
             in parts 'element list', 'species list' and 'initial conc.'
             EDIT asks then for name to identify the line to be changed
 -CHANGE I1: line no. I1 may be changed

 -DELETE:    allows to delete a line
             in parts 'head' and 'chemical equations' EDIT asks then for
             the line number to be changed;
             in parts 'element list', 'species list' and 'initial conc.'
             EDIT asks then for name to identify the line to be changed

 -DELETE I1: deletes line i1

 -QUIT:      leaves this question level

 -RETURN:    leaves subsystem EDIT



 Ith LINE: enter a new valid input line
           or
           enter a comment line ( starts with '*c...'
 QUIT:     stops editing new input lines


 LINE NO.: integer number (this line will be changed/scratched)
 QUIT:     leaves this mode (no change or scratch)


 NAME: enter the name of an chemical species (element) to identify the
       line to be changed/scratched
 QUIT: leaves this mode (no change or scratch)


 MODIFIED LINE: enter a new valid input line
                or
                enter a comment line ( starts with '*c...'
 QUIT:          leaves this mode (old line is not replaced)


 NEW VALUE: enter a valid real value
 QUIT:      leaves this mode


 NEW VALUE: enter a valid real value (old value is replaced)
 DELETE:    deletes current real value (no new value has to be entered)
 QUIT:      leaves this mode


  QUESTION:
  Modify numerical input:
  / LIST / EPS / START-(T) / FINAL-(T) / OUT-(T) /  IPRINT /
  / QUIT / RETURN / ?

  ANSWERS:
  -LIST:       list current values of 'numerical input'
  -EPS:        the required relative accuracy may be changed
  -START-(T):  the starting point for simulation (integration) may be
               changed
  -FINAL-(T):  the final point for simulation (integration) may be
               added, scratched or changed
  -OUT-(T):    additional output point for simulation (integration) may
               be changed
  -IPRINT:     print paraneter for additional chemical output may be
               changed
  -QUIT:       leaves this question level

  -RETURN:     leaves subsystem EDIT


 NEW VALUE: enter a valid value (old value is replaced)
 QUIT:      leaves this mode (no change)


 NEW VALUE: enter a valid value to replace current value
 DELETE:    deletes current value (no new value has to be entered)
 QUIT:      current value is not changed/scratched


 i.th VALUE: enter a valid value (is added to current values)
 QUIT:       leaves this mode (stops editing new output points)




    Papers related to LARKIN:
    =========================

     (1) P.Deuflhard, G.Bader, U.Nowak:
         LARKIN a software package for the numerical simulation
         of LARge systems arising in chemical reaction KINetics.
         In K.H.Ebert, P.Deuflhard, W.Jaeger (eds.): Modelling of
         Chemical Reaction systems.
         Springer Series Chem. Phys. 18 (1981)

     (2) G.Bader, U.Nowak, P.Deuflhard:
         An Advanced Simulation Package for Large Chemical Reaction
         Systems.
         In R. Aiken (ed.): Stiff Computation
         Oxford Univ. Press (1985)


    Papers related to further development of LARKIN:
    ------------------------------------------------

     (1) U.Nowak, P.Deuflhard:
         Towards parameter identification for large chemical reaction
         systems.
         In P.Deuflhard, E.Hairer (eds.): Numerical Treatment of
         Inverse Problems in Differential and Integral Equations,
         Progress in Scientific Computing 2, Birkhaeuser (1983)

     (2) U.Nowak, P.Deuflhard:
         Numerical identification of selected rate constants in
         large chemical reaction systems.
         Applied Numerical Mathematics 1 (1985) 59-75

     (3) U.Nowak, D.Walkowiak:
         Numerical Simulation of Large Chemical Reaction Kinetics
         Including Thermodynamics.
         In preparation


    Papers related to basic integration method:
    -------------------------------------------

     (1) G.Bader, P.Deuflhard:
         A Semi-Implicit Mid-Point Rule for Stiff Systems of Ordinary
         Differential Equations.
         Numerische Mathematik 41, (1983) pp. 373-398

     (2) P.Deuflhard:
         Order and Stepsize Control in Extrapolation Methods.
         Numerische Mathematik 41, (1983) pp. 399-422

     (3) P.Deuflhard:
         Recent Progress in Extrapolation Methods for ODE's.
         SIAM Review  (1985)

     (4) I.S.Duff, U.Nowak:
         On sparse solvers in a stiff integrator of extrapolation
         type.
         Uni. Heidelberg, SFB 123, Tech. Rep. 229 (1986)




