matlab workshop for engineering applications

8/7/2019 MATLAB Workshop for Engineering Applications

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MATLAB Workshop for

Engineering Applications



Table of Contents ± Day One

� Overview

� Basic Interfaces

� Arrays, Matrices, Operators

� Programming

� Data I/O connection



Table of Contents ± Day Two

� Basic Data Analysis

� Numerical Analysis

� Graphics, Data Visualization, Movies� Inter-language Programming

� Control System and matlab

application

� Image Processing



Overview



Matlab

� MATLAB-³MATrix LABoratory´

� Powerful, extensible, highly integrated

computation, programming, visualization,and simulation package

� Widely used in engineering, mathematics,

and science

� Why?



MATLAB¶s Offers

� Interactive code development proceeds

incrementally; excellent development and rapid

prototyping environment

� Basic data element is the auto-indexed array

� This allows quick solutions to problems that can be formulated in vector or matrix form

� Powerful GUI tools

� Large collection of toolboxes: collections of

topic-related MATLAB functions that extend the

core functionality significantly



MATLAB Toolboxes

Math and AnalysisOptimization

Requirements ManagementInterface

Statistics

Neural Network

Symbolic/Extended Math

Partial DifferentialEquations

PLS Toolbox

Mapping

Spline

Data Acquisition and ImportData Acquisition

Instrument Control

Excel Link

Portable Graph Object

Signal & Image Processing

Signal Processing

Image Processing

Communications

Frequency Domain System

IdentificationHigher-Order Spectral Analysis

System Identification

Wavelet

Filter Design

Control Design

Control System Fuzzy Logic

Robust Control

-Analysis and Synthesis

Model Predictive Control



Matlab Web Link!



Matlab Programming

system� Language: arrays and matrices, controlflow, I/O, data structures, user-defined functions and scripts

� Working Environment: editing, variable

management, importing and exporting data,debugging, profiling

� Graphics system: 2D and 3D datavisualization, animation and custom GUIdevelopment

� Mathematical Functions: basic (sum , sin,«)

to advanced (fft, inv, Bessel functions,«)

� API: can use MATLAB with C, Fortran, and Java, in either direction



Matlab tutorial and

help web sites� www.mathworks.com/

� www.mathtools.net/MATLAB

� www.math.utah.edu/lab/ms/matlab/matlab.html

� web.mit.edu/afs/athena.mit.edu/software/matlab/

� www.utexas.edu/its/rc/tutorials/matlab/

� www.math.ufl.edu/help/matlab-tutorial/

� www.indiana.edu/~statmath/math/matlab/links.html

� www-h.eng.cam.ac.uk/help/tpl/programs/matlab.html



Basic Interfaces



Main MATLAB

Interface

Command window

Workspace &Current directory

CommandHistory

Menu bar



MATLAB Development

Windows� Command Window: where you enter commands

� Command History: r unning history of commands which is preserved

across MATLAB sessions

� Current directory: Default is $matlabroot/work

� Workspace: GUI for viewing, loading and saving MATLAB variables� Array Editor : GUI for viewing and/or modifying contents of MATLAB

variables (openvar varname or double-click the array¶s name in the

Wor kspace)

� Editor/Debugger : text editor, debugger; editor wor ks with file types in

addition to .m (MATLAB ³m-files´)



MATLAB Editor

Window



MATLAB Help

Window



Command-Line Help

>> help

HELP topics:

My Documents\MATLAB - (No table of contents file)

matlab\general - General purpose commands.

matlab\ops - Operators and special characters.

matlab\lang - Programming language constructs.

matlab\elmat - Elementary matrices and matrix manipulation.

matlab\elfun - Elementary math functions.

matlab\specfun - Specialized math functions.

matlab\matfun - Matrix functions - numerical linear algebra.

matlab\datafun - Data analysis and Fourier transforms.

matlab\polyfun - Interpolation and polynomials.

matlab\funfun - Function functions and ODE solvers.

matlab\sparfun - Sparse matrices.

matlab\timefun - Time and dates.

matlab\datatypes - Data types and structures.

matlab\verctrl - Version control.

matlab\codetools - Commands for creating and debugging code.

matlab\helptools - Help commands.

matlab\winfun - Windows Operating System Interface Files (COM/DDE)

matlab\demos - Examples and demonstrations.



Command-Line Help

>> help figure

FIGURE Create figure window.

FIGURE, by itself, creates a new figure window, and returns

its handle.

FIGURE(H) makes H the current figure, forces it to become visible,

and raises it above all other figures on the screen. If Figure H

does not exist, and H is an integer, a new figure is created with

handle H.

GCF returns the handle to the current figure.

Execute GET(H) to see a list of figure properties and

their current values. Execute SET(H) to see a list of figure

properties and their possible values.

See also subplot, axes, gcf, clf.

Reference page in Help browser

doc figure



V ariables (Arrays) and

Operators



Variable defination

mixed data types

semi-colon suppresses output of the calculation¶s result

>> 16 + 24

ans =

40

>> product = 16 * 23.24

product =

371.84

>> product = 16 *555.24;>> product

product =

8883.8

No declaration needed



>> clear

>> product = 2 * 3^3;>> comp_sum = (1 + 4i) + (1 - 4i);

>> show_i = i^2;

>> save three_things

>> clear

>> load three_things

>> who

Your variables are:

comp_sum product show_i

>> product

product =

54>> show_i

show_i =

-1

Remove all variables

Save wor kspace variables

Load variables

Show variables

Answer for variables

Define variables



Matlab data type

� The basic data type used in MATLAB is the double precision array

� No declarations needed: MATLAB automatically allocates requiredmemory

� Resize arrays dynamically

� To reuse a variable name, simply use it in the left hand side

� of an assignment statement

� MATLAB displays results in scientific notation ± Use File/Preferences and/or format function to change default� short (5 digits), long (16 digits)

� format short g; format compact (my preference)



Variable names are case sensitive and over-written when re-used

Basic variable class:Auto-Indexed Array

Allows use of entire arrays (scalar, 1-D, 2-D, etc«) as

operands

Vectorization:Always use array operands to get bestperformance (see next slide)

Terminology: ³scalar´ (1 x 1 array), ³vector´ (1 x N array), ³matrix´

(M x N array)

Special variables/functions: ans, pi, eps, inf, NaN, i, nargin,nargout, varargin, varargout, ...

Commands who (terse output) and whos (verbose output) show

variables in Workspace

Matlab data type



t =1:10

t =1 2 3 4 5 6 7 8 9 10

k =2:-0.5:-1

k =2 1.5 1 0.5 0 -0.5 -1

B = [1:4; 5:8]

x =1 2 3 4

5 6 7 8

Long Array, Matrix



Creating Matrices using built in

function

zeros(m, n): matrix with all zeros

ones(m, n): matrix with all ones.

eye(m, n): the identity matrix

rand(m, n): uniformly distributed randomrandn(m, n): normally distributed randommagic(m): square matrix whose elements

have the same sum, along the row,

column and diagonal.

pascal(m) : Pascal matrix.

x = zeros(1,3)

x =

0 0 0

x = ones(1,3)

x =

1 1 1

x = rand(1,3)

x =

0.9501 0.2311 0.6068



Matrix Index

A=[1,2,5;4,6,3;3,6,9]

A =

1 2 54 6 3

3 6 9

A(7)ans =

5

A(3,2)

ans =

6A(2,:)

ans =

4 6 3

A(1:3,3)

ans =5

3

9

A(1,1:3)

ans =1 2 5



Matrix Concatenation

x=[1 4 3]

x =

1 4 3

y=[2 6 3]

y =

2 6 3

z=[0 0 0]

z =

0 0 0

[x y z]

ans =

1 4 3 2 6 3 0 0 0

[x;y;z]

ans =

1 4 3

2 6 30 0 0

Coloumn concatenation

Row concatenation



Matrix Operations

+ addition

- subtraction

* multiplication

/ division

^ powerµ conjugate transpose

A=[1 2 3;8 7 4;2 4 5]

A =

1 2 38 7 4

2 4 5

B=[1 9 6;3 5 2;4 5 9]

B =

1 9 63 5 2

4 5 9

X=A+B

X =2 11 9

11 12 6

6 9 14

Y=A-B

Y =0 -7 -3

5 2 2

-2 -1 -4

Z=A*B

Z =19 34 37

45 127 98

34 63 65

A/Bans =0.1084 -0.072 0.277-0.765 2.343 0.4330.1867 0.042 0.421



Operators

(Element by Element).* element-by-element multiplication

./ element-by-element division

.^ element-by-element power

A = [1 2 3; 5 1 4; 3 2 1]

A =

1 2 3

5 1 4

3 2 -1

x = A(1,:)

x=

1 2 3

y = A(3 ,:)

y=

3 4 -1

b = x .* y

b=

3 8 -3

c = x . / y

c=

0.33 0.5 -3

d = x .^2

d=

1 4 9



>> hi = ' hello';

>> class = 'MATLAB';

>> hi

hi =hello

>>

classclass =

MATLAB

>> greetings = [hi class]

greetings =

helloMATLAB

>>

vgreetings = [hi;class]vgreetings =

helloMATLAB

Character Strings



Matrix sum

sumcol=sum(A)

sumcol =

11 13 12

A=[1 2 3;8 7 4;2 4 5]

A =

1 2 3

8 7 42 4 5

sumrow= sum(A')'

sumrow =6

19

11

sumdiag= sum(diag(A))

sumdiag =

13

sumotherdiag= sum(diag(fliplr(A)))

sumotherdiag =

12