The beginning and ending guard bars are "bar-space-bar" or "" the B in the above table.
There are 2 types of m-file Scripts Functions Scripts are a type of m-file that runs in the current workspace. So if you call a script from the command line base workspace the script will use and manipulate the variables of the base workspace. This can get very messy and lead to all sorts of strange errors when loops are involved and the coder is lazy about naming their loop variables i.
Functions are wholly contained in themselves. They possess their own workspace keeping workspaces separate.
This means that all variables necessary for a particular function must be passed or defined in some way. This can get tedious for complex algorithms requiring lots of variables. However, any manipulations of variables are discarded when the function is exited.
Only those output arguments provided by the function are available to the calling workspace.
This means that loops can use i, j, or k all they want because the function's workspace and the calling workspace do not mix. Any command valid at the command line is valid in any m-file so long as the necessary variables are present in the m-files operating workspace. Using functions properly any change can be affected to any algorithm or plotting tool.
This allows for automation of repetitive tasks. It is optional to end the M-file with 'end'; doing so, however, can lead to complications if you have conditionals or loops in your code, or if you're planning on using multiple functions in the same file see nested functions for details on this.
Requirements for a function[ edit ] Custom functions follow this syntax in their most basic form: Calling the function from the command line or another m-file is done by invoking the m-file name of the function with the necessary input and output arguments.
Within the function itself, there must be a statement that defines each of the output arguments output1, output2, etc. Without some declaration the variable for the output argument doesn't exist in the function's workspace.
This will cause an error about "one or more output arguments". It is good practice to initialize the output arguments at the beginning of the function. Typically output arguments are initialized to empty  or 0 or -1 or something equivalent for other data types.
The reason is that if the function encounters an error you've anticipated then the function can return via the return command with those default values. If the initialization value is an invalid value then it can easily be checked by the calling function for any errors which may not throw a MATLAB error.
Path[ edit ] In order to invoke a function, that function's m-file must be in the current path. There is a default path that can be set up through the File menu or the addpath command. The order of the path is important as MATLAB searches the path in order and stops searching after it finds the first instance of that m-file name.
The current path is the current directory which can be seen at the top of the MATLAB window or by typing pwd at the command prompt the default path Note that MATLAB will always search the current directory before searching any of the rest of the path. The nargin command returns the number of passed input arguments.
This is useful in conjunction with nargchk nargchk min, max, nargin where min is the minimum number of arguments necessary for the function to operate and max is the maximum number of valid input arguments.
The nargout command is useful for determining which output arguments to return. Typically, the outputs are the end results of some algorithm and they are easily calculated. However, in some instances secondary output arguments can be time consuming to calculate or require more input arguments than the primary output arguments do.
So the function can check the number of output arguments being requested through the nargout command. If the caller isn't saving the secondary output arguments then they do not need to be calculated.
The functions and objects come with default values for these properties but the user is allowed to override these defaults.To make life easier, MATLAB includes many standard functions. Each function is a block of code that accomplishes a specific task.
MATLAB contains all of the standard functions such as sin, cos, log, exp, sqrt, as well as many others. This example shows how to create a function in a program file. Add Help for Your Program. Help text appears in the Command Window when you use the help function. Create help text for your program by inserting comments at the beginning.
Writing a MATLAB Program (4 min, 57 sec). MATLAB MATLAB is a software package for doing numerical computation. It was originally designed for solving linear algebra type problems using matrices.
It’s name is derived from MATrix LABoratory. IV Dynamic Programming 53 13 A Cake-Eating Example 53 14 A Discrete, Stochastic, Cake Eating Problem 59 Part I Using MATLAB 1 Preliminaries MATLAB is an abbreviation for MATrix LABoratory.
Preface. This introduction to R is derived from an original set of notes describing the S and S-PLUS environments written in –2 by Bill Venables and David M.
Smith when at the University of Adelaide. We have made a number of small changes to reflect differences between the R and S programs, and expanded some of the material. Best Practices for Programming MATLAB 56 Posted by Loren Shure, January 13, I thought I would share my top goto list of things I try to do when I write MATLAB code.