operator operatorName [ -parameters parameterList ]
[ -sign +/-1 ]
[ -extraIntegrationOrder n ]
[ -useNodalQuadrature ]
[ -useInteriorQuadrature ]
The available operators and their parameters are listed in section 3.2.
The operator command creates a new command and returns the name of this command. The returned command name is used as a reference to the instance of the function and is used to build up the data structure describing a complete model.
Parameter lists are simply ordered lists of strings describing one of a field, a function, or a TCL variable name in the appropriate slot for that particular operator. The string for a function is the value returned by a previous function command.
The default sign is +1. Be very careful with the sign on the recombination operators. They are actually generation operators with the default sign.
-extraIntegrationOrder can be used to reduce or increase the order of the numerical integration used to evaluate the operator. Each operator estimates the optimal order needed based on the order of interpolation of the fields and functions it was given. Some functions, however, provide nonlinear mappings which do not have a finite polynomial series expansion. In these cases, the interpolation order estimate provided by the function may not be adequate for accurate integration.
-useNodalQuadrature and -useInteriorQuadrature allow the user to override the default quadrature used by operators. Reaction operators typically use nodal quadrature which amounts to pointwise evaluation at the nodes of field elements. Most other operators use interior quadrature, which uses an integration scheme appropriate to exactly integrate the fields or functions it is operating on. It is not recommended to change the defaults.