matlab programming for engineers dr. bashir nouri introduction to matlab matlab basics branching...

Matlab Programming for Engineers Matlab Programming for Engineers Matlab Programming for Engineers Matlab Programming for Engineers

Dr. Bashir NOURI

Introduction to MatlabIntroduction to Matlab Matlab BasicsMatlab Basics Branching Statements Branching Statements Loops Loops User Defined Functions User Defined Functions Additional Data Types Additional Data Types Input/Output Functions Input/Output Functions Simulink Toolbox Simulink Toolbox Important Toolboxes (if time is available) Important Toolboxes (if time is available)

Introduction to MatlabIntroduction to Matlab Matlab BasicsMatlab Basics Branching Statements Branching Statements Loops Loops User Defined Functions User Defined Functions Additional Data Types Additional Data Types Input/Output Functions Input/Output Functions Simulink Toolbox Simulink Toolbox Important Toolboxes (if time is available) Important Toolboxes (if time is available)

CH2: MATLAB BASICS

Mechanical Engineering Department

MATLAB PROGRAMMING FOR ENGINEERS

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Objectives:Objectives:

Variables and Arrays

Initializing Variables in MATLAB

Multidimensional Arrays

Subarrays

Special Values

Displaying Output Data

Data Files

Scalar and Array Operations

Hierarchy of Operations

Built-in MATLAB Functions

Introduction to Plotting

Debugging MATLAB Programs

CH2: MATLAB BASICS



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Variables and Arrays Variables and Arrays

The fundamental unit of data in any Matlab program is the Array Any element of the array can

be retrieved by its indexes Arrays could be matrices or

vectors (row or column) Matlab variable is the region

of memory containing an array Matlab variable

letter + (letter, number, _) Variable type:

1. double precession

(real, complex)

2. Character

'How are you?'

a(3,2)

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Creating and initializing variables in MatlabCreating and initializing variables in Matlab

1. Initializing variables in assignment statements

var = expression; var = 40i; var2 = var/5; var = [1 2 3 4];

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1. Initializing variables in assignment statements

a = [0 1+7]; a = [0 8]

b = [ a(2) 7 a]; b = [8 7 0 8]

c(2,3) = 5; c = 0 0 0

0 0 5

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2. Initializing variables with Shortcut Expression

colon operator (:)

first : incr : last

Ex:

x = 1:2:10; x = [1 3 5 7 9]

angles = (0.01:0.01:1)*pi;

f = [1:4]'; if no incr is used default incr=1

(') is the transpose operator.

g = [1:4];

h = [g' g'];

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3. Initializing variables with Built-in Function

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4. Initializing variables with Keyboard Input

my_val = input('Enter an input value: ');

v1 = input('Enter data: ');

v2 = input('Enter data: ', 's');

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Multidimensional ArraysMultidimensional Arrays

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Multidimensional ArraysMultidimensional Arrays

1. Storing Multidimensional Array in Memory

2. Accessing this array with one dimension index

How

the

arr

ay is

sto

red

in c

ompu

ter

mem

ory Array as introduced

CH2: MATLAB BASICS



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SubarraysSubarrays

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SubarraysSubarrays

1. The end Function (highest value of a given subscript)

CH2: MATLAB BASICS



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SubarraysSubarrays

3. Assigning a scalar to

a subarray

2. Left-hand side Subarrays

assignment statement

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Special ValuesSpecial Values

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Displaying Output DataDisplaying Output Data

Default Matlab Format == Four Digits After the Decimal Point

CH2: MATLAB BASICS



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Displaying Output Data (NUMBER FORMAT)Displaying Output Data (NUMBER FORMAT)

CH2: MATLAB BASICS



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Displaying Output Data (disp and fprintf functions)Displaying Output Data (disp and fprintf functions)

CH2: MATLAB BASICS



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Data Files (save)Data Files (save)

save filename var1 var2 var3 *.mat

save filename var1 var2 var3 -ascii text format (ascii)

CH2: MATLAB BASICS



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Data Files (save)Data Files (save)

save filename var1 var2 var3 *.mat

save filename var1 var2 var3 -ascii text format (ascii)

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Data Files (load)Data Files (load)

load filename.mat var1 var2 (*.mat file format, loads specific variables)

load filename.* (any other format, loads all the file

data in the file must have array structure)

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Scalar and Array Operations Scalar and Array Operations

CH2: MATLAB BASICS



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Scalar and Array

Operations

Very important

CH2: MATLAB BASICS



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Scalar and Array Operations Scalar and Array Operations

Matrix left division (a\b)

CH2: MATLAB BASICS



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Hierarchy of Operations Hierarchy of Operations

Distance = 0.5 * acceleration* (time^2)

Distance = (0.5 * acceleration* time)^2

Not the same!

CH2: MATLAB BASICS



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Class Work Class Work

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Built-in Matlab Functions Built-in Matlab Functions

1 . Optional results

2. Most of functions

accept array inputs

Optional

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Built-in Matlab Functions (Common Functions) Built-in Matlab Functions (Common Functions)

CH2: MATLAB BASICS



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Built-in Matlab Functions (Common Functions) Built-in Matlab Functions (Common Functions)

CH2: MATLAB BASICS



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Plotting in MatlabPlotting in Matlab

CH2: MATLAB BASICS



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Printing a Plot / Exporting a Plot as a Graphical Image Printing a Plot / Exporting a Plot as a Graphical Image

>> print <options> <filename>

>> help print (to see print options)

If no filename is specified, plot is printed on the printer

CH2: MATLAB BASICS



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Printing a Plot / Exporting a Plot as a Graphical Image Printing a Plot / Exporting a Plot as a Graphical Image

CH2: MATLAB BASICS



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Multiple plots Multiple plots

Plot the following functions on the same figure

f(x) = sin(2x) and its first derivative over x = 0:pi/100:2*pi

CH2: MATLAB BASICS



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Multiple plots Multiple plots

Plot the following functions on the same figure

f(x) = sin(2x) and its first derivative over x = 0:pi/100:2*pi

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Line Color, Line Style, Marker Style, and Legends Line Color, Line Style, Marker Style, and Legends

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Line Color, Line Style, and Marker Style:

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Legends:

>> legend off (removes the legend from the plot)

>> legend('string1' , 'string1' , … ,'location', 'value from table')

Be aware of the version of Matlab you are using, see help legend

NW NL NC NR NE

TW TL TC TR TE

MW ML MC MR ME

BW BL BC BR BE

SW SL SC SR SE

Limits of plot axes

CH2: MATLAB BASICS



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Logarithmic Scale Logarithmic Scale

>> plot

>> semilogx

>> semilogy

>> loglog

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Example Example

CH2: MATLAB BASICS



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Home WorkHome Work

Solve the following problems

2. [9, 10 , 11, 16]

matlab programming for engineers dr. bashir nouri introduction to matlab matlab basics branching...

Documents

matlab matlab basics

matlab functionsintroduction

debugging matlab programsch2

matlabinitializing variables

arraysinitializing variables

available ch2

inputenter data

computer memory array