Define the termination criteria

Alchemist supports the possibility to write termination conditions for any simulation. Termination conditions are checked after every event, and, if met, cause the immediate termination of a simulation. Termination conditions are expected to be found in the {{ anchor(‘it.unibo.alchemist.model.implementations.terminators’) }} package.

They are defined in the terminate section of the configuration file. Multiple terminators are allowed, the first terminator matching causes the termination of the simulation (they are in and).

Terminating the simulation after some time

One of the simplest terminators availables allows for declaring a simulation completed when a certain simulated time is reached. In the following example, it is used in conjunction with a number of variables, showing how it’s possible to use such variables to produce batches of simulations terminating at different times.

incarnation: protelis

network-model:
  type: ConnectWithinDistance
  parameters: [30]

deployments:
  - type: Rectangle
    parameters: [100, 62, 15, 95, 200]
    contents:
      - molecule: "source"
        concentration: true
        in:
          type: Circle
          parameters: [107.96487911806524, 102.49167432603535, 10]
    programs:
      - time-distribution: 1 # This is a frequency
        program: >
           import protelis:coord:spreading
           distanceTo(self.getDeviceUID().getId() == 0)           
      - program: send

terminate:
  - type: AfterTime
    parameters: 1

Terminating the simulation if the environment is not changing

A terminator is provided for terminating when a simulation is “stable” (nothing changes in terms of positions and nodes’ content). The class implementing it is StableForSteps.