Leveraging Model Comparison to find what you need

Posted by Guy Rouleau, February 1, 2023

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Today I want to share an example of how I sometimes use Model Comparison to answer questions about Simulink blocks or models. While this is obviously a key part of the workflow to merge branches in a project under source control as I described in Three-Way Model Merge and Git, model comparison can also be used to answer subtle "how-to" questions.

Let's look at a simple example question I received today and how I used model comparison to answer it.

The Question

The question I received today is:

"Hi Guy, do you know of a programmatic way to flip a block on the horizontal axis?"

I did not know the response off the top of my head, but here is how I figured it out.

Before and After

The first thing I do in this kind of situation is making an example to confirm my understanding of the question. For that, I created a simple Subsystem with a few ports all around and masked it to make the behavior as obvious as possible. 

Then I made the requested modification interactively, using the Format Tab of the toolstrip:

Comparing Before and After

I saved two versions of this simple model, one before the change, and one after. Then I simply right-clicked on the two files in the Current Folder Browser and selected Compare Selected Files/Folders:

In the comparison results, I disabled the filter for Nonfunctional Changes and I could immediately identify the two parameters needed to flip a block horizontally:

Validating the Results

To confirm that the parameters identified by the Model Comparison were what I needed, I wrote this simple script:

Now it's your turn

Are you sometimes using the Model Comparison tool to identify subtle differences between blocks, Subsystems or models? Or to find the parameter you are looking for?