baseclass.md

Baseclass

baseclasses.py contains code for eFMU class, which handles data exchange of models and controllers. Each eFMU is used to represent a simulator or a controller by implementing an advance/compute function, and storing the inputs, outputs, and logs through the computation. The most common usage is to define a new controller class, inherit the eFMU class, define a compute method, and override the __init__ method.

Important Functions

---

__init__

Initialize the inputs and outputs. By default, they are set as empty dictionaries. You would noramlly override this. The keys of self.input and self.output are the names of the inputs and outputs. Here is an example of the __init__ method of a controller with inputs "a" and "b". The output name is "c".

    class testcontroller1(eFMU):
            def __init__(self):
                self.input = {'a':None,'b':None}
                self.output = {'c':None}

do_step

The function to advance the simulator or controller. It takes in a dictionary and set the values of the inputs according to that dictionary. Then it calls self.__compute__ to perform the computation, which the users needs to implement themselves.

get_model_variables

Return all model or controller input variables as a list.

compute

Abstract method to compute outputs. Return a log message. Users needs to implement this methods in their eFMU subclasses.

get_output

Get the outputs of the model. Argument keys is a list of the outputs to be returned. If keys == [] then all outputs are returned.

Clarification

self.input and self.output are used to store the newest input & output, while self.storage is used to store the history/logs of the input & output values.

Full Example

---

    # Simple multiplier as test controller (extend the eFMU class)
    class testcontroller1(eFMU):
        def __init__(self):
            self.input = {'a':None,'b':None}
            self.output = {'c':None}
        def compute(self):
            self.output['c'] = self.input['a'] * self.input['b']
            return 'Compute ok'
    # Test controller
    controller = testcontroller1()
    # Get all variables
    variables = controller.get_model_variables()
    # Makeup some inputs
    inputs = {}
    for var in variables:
        inputs[var] = 2
    # Query controller
    print('Log-message:', controller.do_step(inputs=inputs))
    print('Inputs:', controller.input)
    print('Outputs:', controller.output)