training program on matlab

7/29/2019 Training Program on MATLAB

1/48

Training Program on MATLAB

by

Dr. A.P. RuhilComputer Centre


2/48

Contents

Introduction to MATLAB

MATLAB Basics

MATLAB Programming Graphics & Animation

Applications

Statistical data analysis


3/48

Introduction to MATLAB

MATLAB (Matrix Laboratory) A special

purpose computer program to perform

optimized engineering and scientific

calculations.

Genesis: In 1960-70 a large number of

subroutines developed for specific

computational purpose in FORTRAN wereorganized into public domain packages for

free distribution.


4/48

MATLAB was originally created as a front

end for LINPACK A group of routines forworking with matrices and linear algebra.

Primary developer Prof. Cleve Moler

(Univ. of New Maxico) founded MathworkInc. to further develop and market the

product (MATLAB) commercially

Most widely used tools for highperformance numerical computations in

engineering and scientific departments.


5/48

Provide interactive working environmentwith hundred of built-in functions for

technical computation, graphics andanimation.

Built-in functions and Tool box: Linearalgebra, Statistical Data Analysis, SignalProcessing, Optimization, PartialDifferential Equations, Artificial NeuralNetwork, Fuzzy Logic, GA, Financial,

Communication, Symbolic Math, DataAcquisition, Database, Image processing,Compiler, External Interface etc.


6/48

Why MATLAB ?

Vector/matrix manipulation is intuitive

Plotting is easy and flexible Toolboxes for specialized functionality

Full programming language suitable for

quick prototyping


7/48

Advantages

Ease of use similar to Basic language

State of the art algorithms

Platform Independence

Predefined and user defined functions

Device Independent Plotting

Graphic User Interface for application

development Interface with C/ C++/ FORTRAN Languages

Matlab Compiler


8/48

Advantages of MATLAB

1-Ease of Use

MATLAB is similar to BASIC language.

Can be used as scratch pad to evaluate

expressions typed at the command line, or it canbe used to execute large prewritten programs.

Programs may be easily modified with the built-in integrated development environment and

debugged with the MATLAB debugger. As it is so easy to use, it is ideal for the rapid

prototyping of the programs.


9/48

2-Platform Independence

MATLAB is supported on many different

Computer systems, providing a large

measure of platform independence. Programs written on any platform will run

on all the other platforms.


10/48

3-Predefined Functions

MATLAB comes complete with anextensive library of functions that providetested and pre-packaged solutions to

many basic technical tasks. In addition to the large library of functions

built into the basic MATLAB language,many special-purpose toolboxes areavailable to help complex problems inspecific areas.


11/48

4-Device-Independent Plotting

MATLAB has many plotting and imaging

commands. The plots and images can be

displayed on any graphical output devicesupported by the computer on which

MATLAB is running. This capability makes

MATLAB an outstanding tool forvisualizing technical data.


12/48

5-Graphical User Interface

MATLAB includes tools that allow users to

interactively construct a graphical user

interface (GUI) for his or her program.With this capability, the users can design

sophisticated data analysis programs that

can be operated by relativelyinexperienced users.


13/48

6-MATLAB Compiler

MATLABs flexibility and platform

independence is achieved by compiling

MATLAB programs into a device-

independent p-code and then interpreting

the p-code instructions at runtime.

7-Interface with C/ C++/

FORTRAN Languages


14/48

Disadvantage

Slow in Interpreter mode

High Cost


15/48

MATLAB Environment

Fundamental data type is Array.

Scalar is also treated as array with one

row and one column

Three most Important windows are:

Command, Figure, Edit/Debug

Examples in Command window (run

MATLAB Environment)


16/48

MATLAB Desktop

Command Window

Launch Pad

History

Current Directory


17/48

Workspace is collection of all created

variables and arrays (who, whos, clear)

Getting Help:

? from menu or typing helpdesk

Type help followed by function name Type lookforfollowed by function/key word

Important Commands (clc, clear)

MATLAB Search Path


18/48

Variables

A variable is a holding place for a valuewhich can be given a name.

Variable Name Rules:

Must begin with a letter followed by anycombination of letters, numbers, and the

underscore.

Only first 31 characters are significant. Name must be unique.

Names are case sensitive


19/48

Double precision occupies 8 bytes or 64 bits

in size

Can hold integer, real, imaginary, or complex

values

Range: 10 ^ -308 to 10 ^ 308

15-16 significant decimal digits

Automatically created by assigning a numericvalue to a variable

V = 1 + I; (creates a complex number)

Numeric Variables


20/48

Consists of scalars or arrays of 16 bit values each

representing a single character

Automatically created by assigning a single character

or a character string to a variable Comment = This is a Character String; (creates a

1x26 character array)

Now show workspace window

Variables can be created at any time

Type of data assigned to variable determines

the type of variable

Character Variables


21/48

Initializing Variables

Assign data to the variables in an

assignment statement(var = expression)

Input data into the variable from Keyboardvar = input(Enter an input value: );

Read data from file


22/48

Useful Commands

who - shows the environment (name ofvariables in workspace)

clear- removes all variables from memory

clear v1 ez - removes variables v1 & ezfrom memory

clf- clears the current figure or graph

clc - clears the command window

Dir- lists current directory

delete fname - deletes file named fname


23/48

Special Values/ Variables

pi(3.14159)

inf infinity

NaN not a number clock current date and time

date current date

eps epsilon ans answer


24/48

Reserved Words

for

end

if

while

function

return elsif

case

otherwise

switch

continue else

try

catch

global persistent

break

MATLAB has some special (reserved)

words that may not be used.


25/48

Displaying Output data

Integer values are displayed as such

Real number up to four decimals

Very small or large number in scientificnotation with exponent

Default format can be changed to: format short 4 digits after decimal (default)

format long 14 digits after decimal

format short e, format short g

format long e, format long g


26/48

Save/ Load Data

MATLAB saves data in MAT file in a

special compact format. (default mode)

Use -ascii option to save data to exchange

data file other than MATLAB (use

extension as .dat)

Save filename var1 var2.

Load filename (to retrieve data from file)


27/48

MATLAB Basics

The fundamental unit of data (variable) in anyMATLAB program is the array. An array is acollection of data values organized into rowsand columns and known by a single name.

Arrays can be classified as either vector ormatrices. The term vector is usually used todescribe an array with only one dimension,

while the term matrix is usually used todescribe an array with two or moredimension.


28/48

MATLAB Matrices

MATLAB treats all variables as matrices.For our purposes a matrix can be thoughtof as an array, in fact, it is stored that way.

Vectors are special forms of matrices andcontain only one row OR one column.

Scalars are matrices with only one rowAND one column.


29/48

Multidimensional Array

2D

3D or more

Arrays are stored in memory in columnmajor order eg. For A(2x2) array elements

are stored as (1,1), (2,1), (1,2), (2,2)

Can be accessed as single array

subscription. Eg. A(3) will be A(1,2)

Subarray


30/48

MATLAB as Scratchpad

MATLAB can do everything a calculator

does

>> (1+4)*3

>> ans= 15


31/48

MATLAB Matrices (Scalar)

A matrix with only one row AND onecolumn is a scalar. A scalar can be

created in MATLAB as follows:

a_value=23 a_value =

23

>>area = pi*2.5^4;

>>x= 1 + 1/2 + 1/3 + 1/4 + 1/5 + 1/6;


32/48

Scalar Operations

Arithmetic Operations between tow

Scalars:

Addition: a + b

Subtraction: a b

Multiplication: a * b

Division: a / b

Exponentiation: a ^ b

Hierarchy: Parenthesis, ^, /, *, +, - from L to R


33/48

MATLAB Matrices (Row Vector)

A matrix with only one row is called a row

vector. A row vector can be created in

MATLAB as follows (note the commas):

rowvec= [12 14 63]

rowvec=

12 14 63


34/48

MATLAB Matrices (Col. Vector)

A matrix with only one column is called acolumn vector. A column vector can becreated in MATLAB as follows (note the

semicolons): colvec= [13; 45;2]

colvec=

1345

2


35/48

MATLAB Matrices

A matrix can be created in MATLAB as

follows (note the gaps AND semicolons):

matrix = [1 2 3; 4 5 6; 7 8 9]

matrix =

1 2 3

4 5 67 8 9


36/48

Extracting a Sub-Matrix

A portion of a matrix can be extracted and storedin a smaller matrix by specifying the names of

both matrices and the rows and columns to

extract. The syntax is: sub_matrix= matrix ( r1 : r2 , c1 : c2 );

where r1 and r2 specify the beginning and

ending rows and c1 and c2 specify thebeginning and ending columns to be extracted to

make the new matrix.


37/48

Array Operation

Performed between arrays on an element-

by-element basis

Array Addition: a + bArray Subtraction: a b

Array Multiplication: a .* b

Array Right Division: a ./ b

Array left Division: a .\ bArray Exponentiation: a .^ b


38/48

Follows the normal rules of linear algebra

such as matrix multiplication

Matrix Multiplication: a * b

Matrix Right Division: a / b %( a * inv(b) )

Matrix left Division: a \ b %( inv(a) * b)

Matrix Operation


39/48

MATLAB Symbols

. . . continue statement on next line

, separate statements and data

% start comment which ends at end ofline

; (1)suppress output

(2)used as a row separator in a matrix

: Specify range


40/48

Numeric Functions

sqrt(x) Calculates the square root of xmod(x, y) remainder or modulo function

exp(x) e raise to power x

log(x) natural logarithm base e

ceil(x) rounds x to nearest integer towards+ve infinity

fix(x) - rounds x to nearest integer towards Zero

floor(x) - rounds x to nearest integer towards -

ve infinityround(x) Rounds x to the nearest integer

Many more


41/48

Matrix Manipulation Function

Diag(x) Extract diagonal elements

Rot90(x) Rotate matrix 90 degree

tril(x) Extract lower triangular part

triu(x) Extract upper triangular partdet(x) Determinant of matrix

rank(x) - No. of linearly independent rows or

columns

trace(x) sum of diagonal elementseig(x) Eigenvalues and eigenvectors

Many more


42/48

Complex Variables

Complex number: c = a +bi

Complex variable is created by assigninga complex value

Operators:+ : for addition

- : for subtraction

* : for multiplication/ : for right division

\ : for left division


43/48

Functions for Complex Numbers

isreal(a)- returns 0 if a is complex number

abs(a) - returns magnitude of complex value

conj(a) -computes the complex conjugate

real(a) - returns the real portion

imag(a) - returns the imaginary portion

Angle(a)- returns the angle of complexnumber


44/48

Scientific problems always seem to involvethe solution of simultaneous linear

equations. For a few equations (two or

three at most) this may be done by hand.

For more than three equations it is

advisable to use a computer. MATLAB can

solve such equations easily.

For example: Solve for x1, x2, and x3satisfying:

Solution of Simultaneous Equations


45/48

For example: solve linear equations for x1,

x2, and x3

5x + 8y + 2z = 3

4x + 6y + 7z = 5

2x + 8y + 2z = 11

Solution:

a = [5 8 2; 4 6 7; 2 8 2];

b = [3; 5; 11];

X = [x; y; z];

X1 = a \ b;


46/48

MATLAB Graphics

MATLAB also provides a powerful set of

graphics commands to create and

manipulate graphics.

Many commands can be entered from the

Figure window.

Advanced commands must be enteredfrom the Command window or a script.


47/48

Simple Plots

plot(x,y)

For example:

x= 0:1:10;

y=x.^210.*x+15;

plot(x,y);

title (Plot of y=x.^2-10.*x+15)

xlabel(x) ylabel(y)

grid on


48/48

Multiple Graphs

It is possible to plot multiple functions on

the same graph. For Example:

x=0:0.1:6;y1 = sin(x);

y2 = cos(x)

plot(x,y1,'r--', x, y2, 'bo');

training program on matlab

Documents