I'm an engineering student from Germany. Whenever we do data analysis or modeling of dynamic systems, the suggested tool by the professors will almost always be Matlab and Simulink, with Python (especially Jupyter Notebooks) gaining more relevance for data analysis recently.

Simulink is a tool for creating graphical block diagrams to model dynamic systems. A block diagram consists of blocks with inputs and outputs. Blocks can be connected to each other in any arrangement and can be selected from a library. Alternatively, a block can consist of any Matlab function. The results of the simulation can be read from an arbitrary point in the block diagram.

This can be used to model mechanical systems, electric circuits, signal processing, or any other dynamic system. Simulink converts the block diagram into a system of differential equations and solves them numerically using Matlab. Simulink is a very useful tool. Not only for modeling systems but also for communicating them to others with the graphical block diagram and for code generation. According to my professors and some research I did, Matlab and Simulink are commonly used in the industry.

The problem is, Matlab and Simulink are very proprietary. In episode 201 of "Talk Python to me", a Professor of Portland Community College stated that with the costs of Matlab licenses, the College could instead open up a new position to add a new lecture to the curriculum. Simulink is also a heavyweight application that can not be easily implemented on a new operating system or CPU architecture, and it has limited compatibility with external programming languages.

There are some existing alternatives to Simulink. For example proprietary products like Wolfram SystemModeler and Collimator (Python based) and some niche open-source software like OpenModelica and Xcos.

When it comes to data analysis and visualization, Python is a very capable alternative to proprietary software like Matlab or Mathematica. Jupyter Notebooks can be great interactive computational reports for education or to communicate data.

Wouldn't it be great to have a similar 'notebook' format for the interactive modeling of dynamic systems? This notebook format could be a derivative of the Jupyter Notebook. The notebook would consist of a graphical block diagram with markups. Blocks could be imported and shared or created as simple python functions. There could be a very simple base solver, that identifies the blocks that are only dependent on time, and then iterates over the system with a fixed time step. More sophisticated solvers could be developed and shared independently. For example, there could be a solver that utilizes SymPy and tries to solve the system symbolically.

The Jupyter Notebook supports different programming languages. Maybe that would be possible for the 'Block Diagram Notebook' as well. If blocks written in an external language could be included in the block diagram, the code generation step could be eliminated from the development process in some cases. if you are modeling a mechanical system with a microcontroller, the block diagram could include the original C code of the microcontroller, instead of some translated version of it.

I know that many people have asked for an open-source alternative to Simulink before. There is also the SimuPy Module by Benjamin Margolis, which can be used to create and simulate block diagrams programmatically in Python. However, it doesn't include a graphical block diagram.

I don't know if this idea is great, stupid, completely redundant, or viable. From my perspective and with the limited experience I have in engineering, an open-source notebook format like this would be very useful for education and possibly in the industry as well. Please give me your feedback.