An event assignment has two components an expression and a target.
All assignments associated with a single event are executed as one unit. This means further updates and checking for new events is done only after all assignments for a single event are carried out.
Expression
This is a mathematical expression which must evaluate to a numeric value.
Target
An assignment target is the object, which will be assigned the value of the expression when the assignment is
carried out. The target must be unique within the list of assignments for one event.
It is obvious that an event assignment target must not be determined by an expression. This rules out any model object of type assignment as well as rates, fluxes, etc. Additionally, it does not make sense to apply assignments to initial values. The values which are left are the transient values (for species we use concentration) of model entities of type ODE, reaction, or fixed. We limit the event assignment target for species to the concentrations since we do the same for initial values and assignments.
Please note that local kinetic parameters are allowed as targets.
Resolution of Simultaneous Events
It is possible that simultaneously
executed assignments have the same target (
simultaneous events). This situation is not resolved and will lead to an interuption of the integration with an appropriate error message.
Processing
Multiple assignments must be
carried out simultaneously. To achieve this we split the process into two steps:
- calculate the expression.
- execute the target assignment
