MATLAB Examples

Compare and Merge Simulink Models

This example shows you how to use the Simulink® Model Comparison to view and merge the changes between two Simulink models.


This example shows you how to use the Simulink Model Comparison comparison to understand what has changed between two different designs. An engineer has made some changes to the model slxml_aircraft1 and the resulting model is slxml_aircraft2. The Simulink Model Comparison report will show you what these changes are and enable you to create another model containing changes from each of the two source models.

Compare The Models

Setup the example files by running the following command.

% Then use visdiff to compare the models.
visdiff('slxml_aircraft1', 'slxml_aircraft2');

Understand The Results

The Comparison Tool shows a report that only includes the differences between the two models, not the complete model hierarchies.

Colors indicate if items have been modified (purple items), inserted (blue items), or deleted (yellow items).

Stepping Through Differences

Use the "Next" and "Previous" navigation buttons on the Comparison tab to step through groups of changes in the report. When you do this to select an item:

  • The report highlights the corresponding item in the other tree (if it exists)
  • Both models display next to the report. The report highlights the corresponding item in the Simulink model, if possible.

You can control highlighting in the highlight toolstrip section.

Filtering Results

It is possible to control the type of changes the comparison report is displaying by using filters. To see the available filters, and whether or not they have been applied to the current report, click the Filter button in the filter toolstrip section.

For example, some information in the Simulink Model file is defined as being "nonfunctional". These are changes that are unlikely to change the behavior of the design. Nonfunctional items are hidden by default and they can be shown by deselecting the 'Hide Nonfunctional Changes' item in the 'Filters' toolstrip menu dropdown.

Publish Results

It is possible to create a document containing a record of the changes made to a Simulink model using the "Publish" toolstrip option. Select the 'HTML' publish menu item to create an HTML report. Microsoft Word® reports can also be created by using the 'Word' menu item.

Merge Changes in Simulink Models

You can merge the changes between the two Simulink models by clicking the 'Merge' button in the toolstrip. This creates a third file, 'targetFile', which can contain the changes from either the left model (slxml_aircraft1) or right model (slxml_aircraft2). To select which changes you would like in the target file use the radio buttons in the right of the report.

Once you have selected the changes you want in the target model you can save these changes over the right model (slxml_aircraft2) using the 'Save File' toolstrip button.

Note that in order for the tool to automatically connect merged lines, you must merge blocks before lines.

Further Information

Compare Simulink Models