Creating an event with intensity of type interaction

Creates an event whose intensity depends on an individual and interactions with the population. When the event occurs, something happens to an individual I in the population. The intensity of the event can depend on time, the characteristics of I and other individuals in the population, and can be written as $$d(I,t,pop) = \sum_{J \in pop} U(I,J,t),$$ where \(U\) is called the interaction function. The created event must be used with mk_model.

mk_event_interaction(
  type,
  name,
  interaction_code,
  kernel_code = "",
  interaction_type = "random"
)

Arguments

type

Must be one of 'birth', 'death', 'entry', 'exit', 'swap' or 'custom'. See details.

name

(Optional) If not specified, the name given to the event is its type.

interaction_code

String containing some C++ code describing the interaction function. See details.

kernel_code

String containing some C++ code describing the event action. Optional for 'birth', 'death' and 'exit' events. See details.

interaction_type

(Optional) Either 'random' or 'full'. By default 'random' which is faster than 'full'.

Value

An S3 object of class event of type interaction.

Details

The type argument is one of the following

'birth'

By default, a new individual newI is created, with the same characteristics of the parent I and birth date equal to the current time. Optional code can be precised in kernel_code.

'death'

By default, the individual I dies. Optional code can be precised in kernel_code.

'entry'

A new individual newI is added to the population, and its characteristics have to be defined by the user in the entry kernel_code.

'exit'

An individual I exits from the population. Optional code can be precised in kernel_code.

'swap'

The user can change the characteristics of the selected individual I. This requires kernel_code.

'custom'

None of the above types, the user defines kernel_code that can act on the selected individual I and on the population pop.

The interaction_code argument is a string containing some C++ code describing the event interaction function $U$ at time t. The interaction value must be stored in the variable result. Some of available variables in the C++ code are: t (the current time), I (the current individual selected for the event), J (another individual if interaction_type is 'random'), the name of the model parameters (some variables, or functions, see mk_model). See vignette('IBMPopSim_Cpp') for more details.

The kernel_code argument is a string containing some C++ code which describing the action of the event. Some of available variables in the C++ code are: t (the current time), pop (the current population), I (the current individual selected for the event), newI (the new individual if 'birth' or 'entry' event), the name of the model parameters (some variables, or functions, see mk_model). See vignette('IBMPopSim') for more details.

See also

mk_model, mk_event_poisson, mk_event_inhomogeneous_poisson, mk_event_individual.

Examples

death_interaction_code<- " result = max(J.size -I.size,0);"
event <- mk_event_interaction(type="death",
                             interaction_code = death_interaction_code)