Part 5. Composing the model

Now that we have our three model components, we can switch from the role of a model component developer into the role of a model composer and compose the three model components into an actual model:

• Copy templates/models/SOME_MODEL.py into pycopancore/models, rename it to my_exploit.py, and edit it to have:

  from ..model_components import my_exploit_growth as growth
  from ..model_components import my_exploit_fishing as fishing
  from ..model_components import my_exploit_learning as learning
  
  ...
  
  class Cell(growth.Cell,
             fishing.Cell,
             base.Cell):
      """Cell entity type."""
      pass
  

Thereby you say which components the model has and which of them contribute to the Cell entity type. The final Cell class is composed via multiple inheritance from the mixin classes provided by two of our model components, and the basic Cell mixin class shipped within the base model component. Note that base.Cell must always be named last in the list. (Despite this, the order is almost arbitrary and matters only when different components define the same attribute or method in different ways.)

• In the same way as for Cell, edit the definitions of the classes Individual, Environment, Metabolism, and Culture:

  class Individual(fishing.Individual,
                   learning.Individual,
                   base.Individual)...
  
  class Environment(growth.Environment,
                    base.Environment)...
  
  class Metabolism(fishing.Metabolism,
                   base.Metabolism)...
  
  class Culture(learning.Culture,
                base.Culture)...
  

• Even though we do not explicitly use them, all pycopancore models must also contain the World and SocialSystem entity-types, so we need to keep also:

  class World(base.World)...
  
  class SocialSystem(base.SocialSystem)...
  

The latter is because every Individual must belong to some SocialSystem and every Cell to some World, hence we will have one object each of those later on.

• Finally, also compose the Model class that will serve as the main entry-point for pycopancore’s runner, and edit its metadata:

  class Model(growth.Model,
              fishing.Model,
              learning.Model,
              base.Model):
      name = "exploit tutorial"
      description = "tutorial version of the copan:EXPLOIT model"
      entity_types = [World, SocialSystem, Cell, Individual]
      process_taxa = [Environment, Metabolism, Culture]
  

Now the model is ready to be used in a study: Part 6: Using the model for a study