Plots and GUI
|In this section we talk about some very
basic features and commands.
This is a type of Matlab help. To begin with, we look
at the general structure of the environment.
Typing 'help function'
Matlab command window), with the appropriate function or command name,
detailed help for any of the functions or commands available. We
encourage the use of the online Matlab help.
This is the main window. It is characterized by the MATLAB command
prompt '>>'. When you launch the application, MATLAB puts
you in this window. All commands are typed here, at the MATLAB prompt.
All commands typed on the MATLAB prompt in the command window get
recorded, even across multiple sessions. You can select a command from
this window with the mouse and execute it in the command window by
double clicking on it. You can also select a set of commands from this
window and create an m-file with the right click of the mouse, and also
selecting the appropriate option from the menu.
This subwindow lists all variables that you have generated so far and
shows their type and size. You can do various things with these
variables by clicking on a variable and then using the right button on
the mouse to select your option.
This is where all your files from the current directory are found. You
can do file navigation here. You also have several options of what you
can do with a file once you select it. To see the options, click the
right button of the mouse after selecting a file. You can run m-files,
rename them, delete them, etc.
This is where you write or edit and save your own programs in files
called 'M-files'. You can use any text editor to carry out these tasks.
MATLAB provides its own built-in editor. However, you can use your own
editor by typing the standard file-editing command that you normally
use on your system.
The output of all graphics commands typed in the command window is
flushed to the Graphics or Figure window, a separate window with white
The MATLAB help has a demo facility to show many of its features. The
includes a tutorial introduction that is worth trying. Type 'demo' at
the MATLAB prompt to invoke the demonstrations, and follow the
The MATLAB help provides on-line examples for all its built-in
programming language commands. You can get Matlab help just typing
on your command window. You'll see fast-helpful
MATLAB supports interactive computation, taking the input from the
screen, and flushing the output to the screen. Additionally, it can
read input files and write output files.
The fundamental data type in MATLAB is the array. It includes several
distinct data objects: integers, real numbers, matrices, strings,
structures, and cells. In most cases you never worry about the data
type or object declarations. MATLAB automatically sets its variables to
match what you need.
Dimensioning is automatic in MATLAB. No dimension statements are
required for vectors or arrays. You can find the dimensions of an
existing matrix or a vector with the 'size' and 'length' commands.
MATLAB is case-sensitive; that is, it differentiates between the
lowercase and uppercase letters. Thus 'm' and 'M' are different
variables. MATLAB commands and function are typed in lowercase letters.
The output of every command is displayed on the screen unless MATLAB is
directed otherwise. A semicolon at the end of a command suppresses the
screen output, except for graphics.
Computations in MATLAB are performed using double precision, but
the appearance of floating point numbers on the screen is controlled by
the 'format' in use. There are several different output formats. The
following list shows the 'pi' value in several formats:
|format short e
The formats 'format compact' and 'format loose' control the spacing
above and below the displayed lines. The default is format short.
MATLAB saves previously typed commands in a buffer. These commands can
be recalled with the up-arrow key (this helps in editing previous
commands). You can also copy and paste commands from the 'Command
History' subwindow where all your commands from even previous sessions
of MATLAB are recorded and listed.
are standard ASCII text files, with a '.m' extension. There are two
types of these: script files and function files. Most of the programs
that you write in MATLAB are saved as M-files. All built-in functions
are M-files, most of which reside on your computer in a special format.
are binary data-files, with a '.mat' extension to the filename.
Matfiles are created by MATLAB when you save data with the 'save'
command. The data are written in a special format that only MATLAB can
read. These files can be loaded into MATLAB with the 'load' command.
are MATLAB-callable Fortran and C programs, with a '.mex' extension to
directory and saving files
In MATLAB, there's a default folder called 'work' where MATLAB saves
your files if you do not specify any other location. However, it is
better if you create a separate folder for saving your work. If you
need to store your files somewhere else, you might have to specify the
path to the files using the 'path' command, or change the working
directory of MATLAB to the desired directory with the 'cd' command.
On PCs, you can print the contents of your current active window
(command, figure, or edit window), select Print... from the File menu
and click Print in the dialog box.
Starting with MATLAB 6, Mathworks (the MATLAB creators)
new features to easily navigate through your files. The 'Current
Directory' is shown just above the Command Window with the option of
changing the current directory with just a click. In addition, there is
a 'Current Directory' subwindow to the left of the Command Window that
lists files in the current directory (you can show/hide it from the
'Desktop menu'), and gives you the option of opening, executing,
editing, etc., with the click of the right button on your mouse. You
can also change the directory there or add a particular directory to
the MATLAB path so that it can access all the files in that directory
'Matlab Help' to home
'Matlab Help' to 'Help Menu'