Convert State to Stateful Parameter about mdf HOT 4 CLOSED

Apart from parameters nodes also have stateful parameters whose values are associated with a function and evolves with time as the graph is evaluated.
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A stateful parameter has the following components:

1. id
2. default initial value to start with
3. value updated by a MDF function that uses the previous value of the stateful parameter, time increment (dt)

Initial work on this here: https://github.com/ModECI/MDF/tree/stateful_parameter

Initial thoughts on implementing the translator:

1. Input should be any json file with implementation of states.
2. Extract the parameters / arguments from the expression of time derivative, parameters field of the nodes.
3. Create a new MDF function using the expression of time derivative for each state, extracted arguments.

from mdf.

from mdf.

Translator has been implemented and tested successfully. Translator converts files with state if it contains to file with stateful parameters, otherwise unchanged. The output file upon evaluation produces the same results.
Steps to implement translator

1. import the original json file to be translated
2. if node object has states and time derivative then add 'dt' to the parameters of the node object and add 'time' as a stateful parameter
3. create functions for time_derivative expression for each state variable
4. Replace all names containing states into stateful_parameters
5. While evaluating the graph of the translated version, add the corresponding MDF functions

file location: src/modeci_mdf/full_translator.py
currently on branch 'stateful_parameter': https://github.com/ModECI/MDF/blob/stateful_parameter/src/modeci_mdf/full_translator.py

from mdf.

Translator code merged

from mdf.