A model is the aggregation of all of the systems and fixed (dirichlet) boundary conditions that implements a multi-region system of PDEs. A model provides the coupling of the multi-region physics into a single system of nonlinear equations. A system provide the coupling within a region.
model -systems systemList [ -fixedBC dirichletList ]
[ -atEachTimeStep script ] [ -preSolve script] [
-postSolve script ]
List elements in the fixed boundary conditions are region/field pairs specifying where field values are fixed.
Each fixed (dirichlet) boundary conditions is a list containing a field name and a region name.
-atEachTimeStep allows the user to specify a TCL script that gets executed after each time step. The user can checkpoint solutions or modify TCL variables used in the operators or functions. The TCL variables SOLVE_TIME and TIME_STEP are available if tagged global variables within the script.
-preSolve and -postSolve allow the user to specify a TCL script that gets executed before or after the the solution method. These are intended to be used for validity checking (e.g. to ensure that necessary fields are actually part of the domain) or to create and destroy additional fields that may be needed as part of the solution process (e.g. trapped dopant at an interface).