Main Content


Array of rules in model object


The Rules property shows the rules in a Model object. Read-only array of SimBiology.Rule objects.

A rule is a mathematical expression that modifies a species amount or a parameter value. A rule defines how certain species and parameters should interact with one another. For example, a rule could state that the total number of species A and species B must be some value.

You can add a rule to a model object with the addrule method and remove the rule with the delete method. For more information on rules, see addrule and RuleType.


Applies toObject: model
Data typeArray of rule objects
Data valuesRule object


  1. Create a model object, and then add a reaction object.

    modelObj = sbiomodel ('my_model');
    reactionObj = addreaction (modelObj, 'a + b -> c + d');
  2. Add a rule.

    ruleobj = addrule(modelObj, '10-a+b')

    MATLAB® returns:

    SimBiology Rule Array
    Index:    RuleType:    Rule:
     1        algebraic    10-a+b