Matlab basic commands

Command	Description
exit	Terminate MATLAB
finish	MATLAB termination M-file
matlabrc	MATLAB startup M-file for single-user systems or system administrators
prefdir	Directory containing preferences, history, and layout files
preferences	Open Preferences dialog box for MATLAB and related products
quit	Terminate MATLAB
clc	Clear Command Window
commandhistory	Open Command History window, or select it if already open
commandwindow	Open Command Window, or select it if already open
diary	Save session to file
matlabcolon (matlab:)	Run specified function via hyperlink
perl	Call Perl script using appropriate operating system executable
unix	Execute UNIX command and return result
demo	Access product demos via Help browser
echodemo	Run M-file demo step-by-step in Command Window
help	Help for MATLAB functions in Command Window
helpbrowser	Open Help browser to access all online documentation and demos
helpwin	Provide access to M-file help for all functions

Workspace

assignin	Assign value to variable in specified workspace
clear	Remove items from workspace, freeing up system memory
evalin	Execute MATLAB expression in specified workspace
exist	Check existence of variable, function, directory, or Java class
openvar	Open workspace variable in Array Editor or other tool for graphical editing
which	Locate functions and files
workspace	Open Workspace browser to manage workspace
uiimport	Open Import Wizard to import data

sparse	Create sparse matrix
zeros	Create array of all zeros

Publishing

grabcode	MATLAB code from M-files published to HTML
notebook	Open M-book in Microsoft Word (Windows)
publish	Publish M-file containing cells, saving output to file of specified type

loops and dairy files in matlab

Loops

A loop specifies that a command or group of commands should be repeated several times

The easiest way to create a loop is to use a for statement.

f = 1;

for n = 2:10

f = f*n;

end

f

use a semicolon to suppress intermediate output within the loop

To see the final output, we then needed to type f after the end of the loop.

Diary Files

The first diary command causes all subsequent input to and output from the Command Window to be copied into the specified file

By using delete at the beginning of the M-file, you ensure that the file only contains the output of the current script.If you omit the delete command, then the diary command will add any new output to the end of an existing file and can end up containing the results of several runs of

the M-file

Mention  at the starting

delete task1.txt

diary task1.txt

echo on

The script M-file should then end with the commands

echo off

diary off

You can also get extraneous output in a diary file if you type CTRL+C to halt a script containing a diary command. If this happens, you should type diary off in the Command Window before running the script again.

M-files and structuring M-files in matlab

M-Files

the Command Window and its history mechanism are insufficient in some cases

A much better approach is to create an M-file. There are two different kinds of M-files

1. script M-files

2. function M-files.

M-files are ordinary text files containing MATLAB commands where you can create and modify them.

you can use the built-in Editor/Debugger

Echoing Commands

echo:

the commands in a script M-file will not automatically be displayed in the Command Window. If you want the commands to be displayed along with the results, use echo

echo on

format long

x = [0.1, 0.01, 0.001];

y = sin(x)./x

echo off

Adding Comments.

to get the explanation of the command used

echo on

% Turn on 15 digit display

format long

x = [0.1, 0.01, 0.001];

y = sin(x)./x

% These values illustrate the fact that the limit of

% sin(x)/x as x approaches 0 is 1.

echo off

Structuring Script M-Files.

the script should be self-contained, unaffected by other variables that you might have defined elsewhere in the MATLAB session

clear all: you can type the line clear all at the beginning of the script, to ensure that previous definitions of variables do not affect the results.

close all command at the beginning of a script M-file that creates graphics, to close all graphics windows and start with a clean slate

% Remove old variable definitions

clear all

% Remove old graphics windows

close all

% Display the command lines in the command window

echo on

% Turn on 15 digit display

format long

Fine-Tuning Your M-Files

1. Include clear all and close all at the beginning of the M-file.
2. Use echo on early in your M-file so that you can see “cause” as well as “effect”.
3. If you are producing graphics, use hold on and hold off carefully.
4. In general, you should put a pause statement after each hold off.
5. Otherwise, the next graphics command will obliterate the current one, and you won’t see it.
6. Do not include bare print statements in your M-files. Instead, print to a file.
7. Make liberal use of pause.
8. Finally, remember that you can stop a running M-file by typing CTRL+C.This is useful if, at a pause or input statement, you realize that you want to stop execution completely.

 

how to get started on matlab basics

Online Help

You can access the online help in one of several ways. Typing help at the command prompt will reveal a long list of topics

help general :see a long list of “general purpose” MATLAB commands

help solve: to learn about the command solve

helpwin or helpdesk at the command prompt to access the online help

syms to declare the variables

syms x y

(x - y)*(x - y)^2

expand(ans)

factor(ans)

Symbolic Expressions

simplify, which you can sometimes use to express a formula as simply as possible

simplify((x^3 - y^3)/(x - y))

arithmetic with symbolic expressions.

cos(pi/2)

cos(sym(’pi/2’)) - cosine of the symbolic representation of π/2

use of sym

create a string consisting of the characters pi/2 and prevent MATLAB from evaluating pi/2 as a floating point number. The command sym converts the string to a symbolic expression

to calculate the values of sin(0.1)/0.1, sin(0.01)/0.01, and sin(0.001)/0.001

x = [0.1, 0.01, 0.001];

y = sin(x)./x

 

What is image processing and matlab

An image is a 2-D function f(x,y) where x and y are spatial coordinates and the amplitude f at any pair of co-ordinates (x,y) is called the intensity values of the image at that point. Digital image  is composed of a finite number of elements each of which has a particular location and value. These elements are called as image elements, pels, pixels. Pixel is used to denote the elements of a digital image

Matlab is a high-performance language for technical computing.  It integrates computation, visualization, and programming in a easy environment. It is an interaction matrix laboratory. ve system  whose data element is an array that doesn’t require dimensions

The name MATLAB stands for matrix laboratory. Matlab is standard computational tool for introductory and advanced courses in mathematics and engineering. The image processing toolbox is a collection of MATLAB functions called m-files that extend the capability of the MATLAB environment to image processing problems

Matlab Windows

the start of Matlab it shows four different windows namely ‘command window’, ‘command history’, ‘Workspace’, ‘Current folder’.

1.      Command Window: This is the pace where the commands are to be written.
2.     Command History: This is the space where the executed commands are stored for future reference or use.
3.      Workspace: This window contains all the variables generated during the work for reference, so it is always advised to choose the name of the variables in relation to the work.

4.      Current Folder: This window shows the current directory in which you are working or the place where the current files will be stored.

MATLAB:

is a high-performance, high-level language.
stands for Matrix Laboratory
can be used as a fancy calculator
allows you to easily work with entire matrices rather than one number at a time
is useful for anything that requires matrix and vector manipulations such as:
Mathematical, scientific, engineering, statistical and financial problems
Anything that requires plotting/visualizing and analyzing data
comes with a basic set of tools for visualizing data and for performing calculations on matrices and vectors
For specific technologies, MATLAB provides toolboxes, which add to the basic MATLAB functionality. We have the Image Processing Toolbox. Some other toolboxes include:

• Statistics Toolbox
• Neural Network Toolbox
• Fuzzy Logic Toolbox
• Signal Processing Toolbox
• Wavelet Toolbox
• Financial Toolbox
• Bioinformatics Toolbox
• Database Toolbox