Efficiently Calling Functions from Other Files in Matlab

In this comprehensive guide, we’ll delve into the fundamentals of calling a function from an external file within MATLAB. By utilizing this technique, you can effectively organize and manage your code …

Updated October 14, 2023

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In this comprehensive guide, we’ll delve into the fundamentals of calling a function from an external file within MATLAB. By utilizing this technique, you can effectively organize and manage your code base for greater efficiency, reusability, and maintainability. The article will explain how this process works in detail, highlighting its importance and real-world applications with code samples.


Matlab is a powerful programming language and interactive environment designed to enable data analysis, algorithm development, and numerical computation. One key aspect of this versatile software is the ability to call functions from different files, allowing for modularized code organization. In this article, we will explore how to efficiently call functions in MATLAB from other files while adhering to best practices for cleaner, more maintainable code.

Why Call Functions Between Files?

There are several reasons to use function calling across different files:

  • Separation of concerns: Dividing the code base into smaller and focused files aids in better understanding and managing large projects, making it easier for other developers to collaborate on the project.
  • Modularity and reusability: By separating functions into individual files, you can easily reuse those components across different parts of your program, resulting in significant time savings during development.
  • Code reuse: Sharing functions between files makes it possible to utilize a function from one file in another without copying the code itself, reducing redundancy and ensuring consistency throughout your code base.
  • Organizational structure: Proper organization of code into separate files helps to improve readability and enhance code maintenance by allowing for better understanding of different aspects of the project.

Requirements for Function Calling Between Files in Matlab

  1. Understand how function definition works in MATLAB
  2. Comprehend variable scopes within functions
  3. Learn how to access variables from one file into another using global or persistent variables
  4. Know the syntax to call a function from an external file
  5. Be aware of potential issues and limitations when working with multiple files

Prerequisites: Functions and Variables in Matlab

Before moving on, it’s important to understand some essential concepts related to functions and variables in MATLAB. Functions are self-contained pieces of code that perform a specific task or compute a result. They can be defined as either global or local depending on their visibility. Variables, in contrast, represent data values within the program which may change throughout execution.

Global vs. Local Scopes

In MATLAB, there are two types of variable scopes: global and local. Global variables are accessible from anywhere within your script, while local variables are confined to their respective functions. It’s crucial to understand that when using a function, you need to explicitly declare any dependent variables as either global or local inside the function definition.

Global Variables in Matlab

Global variables can be accessed by multiple functions and files throughout the program, allowing for shared data among different parts of the code base. In MATLAB, global variables should generally be declared at the beginning of a script before any function definitions. It is important to note that using too many global variables may lead to spaghetti-like code, which can make it difficult to maintain and troubleshoot.

Local Variables in Matlab

On the other hand, local variables are limited to their respective functions and are not visible outside of them. They facilitate encapsulation within a function, which is beneficial for reducing coupling between different parts of your program and improving readability. Local variables can be declared within a function definition using the “local” keyword or by simply defining them without specifying the variable’s scope.

Using Global Variables in External Files

To access global variables in external files, you can declare the global variable name as a public entity (by omitting the “global” keyword) inside that file and use it according to its assigned purpose. This allows for information sharing between multiple parts of your code base without having to rely on functions explicitly. It’s essential to understand how to handle such variables in a safe and efficient manner while using them across different files.

Calling Functions from Other Files in Matlab

To call a function from another file, there are several steps involved:

  1. Create the main MATLAB script file (caller.m) where you want to invoke the function. In this example, let’s assume we have the file “functions.m” containing a function named “my_function” that takes an input argument.
  2. Ensure that both the main script (“caller.m”) and the external file with the function definition (“functions.m”) are located in the same folder or search path within MATLAB’s working directory.
  3. Write your code in “caller.m” to call the function from “functions.m”. For example, if the syntax for calling a function is my_function(argument), you can replace ‘my_function’ with its fully qualified name (including file path) as shown below: functions/my_function(argument).
  4. Run the main script in MATLAB by typing “caller” at the command prompt, or use the run button in the IDE to execute both files and see the output from your function call.

Handling Global Variables and Function Calling in Matlab

In MATLAB, it is essential to take caution when using global variables within a program as there are certain limitations to consider:

  1. Potential name conflicts can arise if two different variables share the same name but are defined in separate files. To avoid this issue, use meaningful and unique variable names or reorganize your code structure to minimize the chances of encountering these conflicts.
  2. Global variables may lead to a lack of cohesion, where multiple functions become interdependent on shared data. This could make it challenging to understand how each part of your program operates independently or contribute to the final output. In such cases, consider using more localized variables or structuring your code around proper function encapsulation.
  3. Sharing global variables across multiple files can result in unwanted side effects due to unintended changes within a file affecting the other parts of the program. To prevent these unwanted consequences, use global variables judiciously and minimize their usage when possible.


Understanding how to call functions from different files is an essential skill for every Matlab developer as it allows for more organized and maintainable code organization. By mastering the concepts related to variable scopes, managing global and local variables effectively, and ensuring proper function calling syntax, you can develop efficient and robust applications that leverage the full potential of MATLAB’s capabilities. Keep in mind the importance of following best practices while working with external files to maintain the integrity of your code base and ensure optimal performance.