Overview of MATLAB Function Types :: Types of Functions (Programming)

Programming

Overview of MATLAB Function Types

There are essentially two ways to create a new function in MATLAB: in a command entered at run-time, or in a file saved to permanent storage.

The command-oriented function, called an anonymous function, is relatively brief in its content. It consists of a single MATLAB statement that can interact with multiple input and output arguments. The benefit of using anonymous functions is that you do not have to edit and maintain a file for functions that require only a brief definition.

There are several types of functions that are stored in files (called M-files). The most basic of these are primary functions and subfunctions. Primary functions are visible to other functions outside of their M-file, while subfunctions, generally speaking, are not. That is, you can call a primary function from an anonymous function or from a function defined in a separate M-file, whereas you can call a subfunction only from functions within the same M-file. (See the Description section of the function_handle reference page for information on making a subfunction externally visible.)

Two specific types of primary M-file functions are the private and overloaded function. Private functions are visible only to a limited group of other functions. This type of function can be useful if you want to limit access to a function, or when you choose not to expose the implementation of a function. Overloaded functions act the same way as overloaded functions in most computer languages. You can create multiple implementations of a function so that each responds accordingly to different types of inputs.

The last type of MATLAB function is the nested function. Nested functions are not an independent function type; they exist within the body of one of the other types of functions discussed here (with the exception of anonymous functions), and also within other nested functions.

One type of function that is not discussed in this chapter is the MATLAB built-in function. Built-ins are defined only as executables internal to MATLAB. See Built-In Functions for more information.

Types of Functions Anonymous Functions