ENG004 ALGORITHMS & INT. TO PROGRAMMING

Week 3

“An introduction to arrays and matrices”

Ahmet Anıl Dindar

07.03.2007

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The class facts

E-mail address: iku.eng004.01@gmail.com

Class web page: http://web.iku.edu.tr/courses/insaat/eng004/

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Last week

What is Algorithm and Programming? Why do we need programs? A powerful tool- MATLAB What is MATLAB? Why MATLAB? How to use it? The first commands in

MATLAB.

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This week

Variables Defining a new variable Assigning a value to a variable Variable types

An introduction to arrays and matrices Entering arrays and matrices Creating arrays and matrices manually by entering

values. Generating arrays and matrices by defining certain rules Creating arrays from existing arrays By using built-in matrix generators

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Variables

What is variable?

Homer Simpson

Are there anyonewhose name is

Homer Simpson?(probably)

YES

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Variables: Variable is a tag given to a specific matrice,

number or anything. You can change the content of the variable any

time. You can name a variable with alphabetic or alpha-

numeric. The variables are important in programming. A good sense and logic is essential to follow the

codes.

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And now let’s see How it is in MATLAB!

Follow me now!

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>> a=1a = 1 >> a=1

a = 1>> a+aans = 2

Variables in MATLAB (Alphabetic):

>> a=1a = 1>> a+aans = 2>> a*aans = 1

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>> a1=10a1 = 10

>> a1=10a1 = 10>> a1a1 = 10

Variables in MATLAB (Alphanumeric):

>> a1=10a1 = 10>> a1a1 = 10>> a1*(2*a1)/5ans = 40

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>> a=10a = 10>> a1=5a1 = 5>> a+a1ans = 15>> a+a1*(a-a1)ans = 35>>

Variables in MATLAB:

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An introduction to arrays and matrices What is matrice? What is array? What are the matrices we use? What are the calculations? The properties of the matrices?

The matrices named with variables?

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Creating a Matrice

>> a=[1 3 4]a = 1 3 4

>> a1 = 1 2 3

Row Matrix (Vector)

Column Matrix (Vector)

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Creating a Matrice

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

An Ordinary Matrice

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Generating arrays and matrices by defining certain rules:

>> a=(1:10)a = Columns 1 through 7 1 2 3 4 5 6 7 Columns 8 through 10 8 9 10

Generic Creation (one by one):

>> deli=(1:2:10)deli = 1 3 5 7 9>>

Generic Creation (two by two):

>> deli=(10:-2:0)deli = 10 8 6 4 2 0

Generic Creation (???):

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Generating arrays and matrices by defining certain rules:

>> ones(1,10)ans = 1 1 1 1 1 1 1 1 1 1>> zeros(1,5)ans = 0 0 0 0 0

Some Special Matrices

What about a matrice with full of 2’s>> twos(1,5)

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Generating arrays and matrices by defining certain rules:

>> ones(1,10)ans = 1 1 1 1 1 1 1 1 1 1>> zeros(1,5)ans = 0 0 0 0 0

Some Special Matrices

What about a matrice with full of 2’s>> twos(1,5)

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Creating matrices from matrices

>> a=(1:5)a = 1 2 3 4 5>> b=(2:6)b = 2 3 4 5 6>> c=[a;b]c = 1 2 3 4 5 2 3 4 5 6

Using matrices to create new matrices

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Assignment

There is not any assignment!

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Next week...

Weeks Date Class Assignment

1 21.02 Introduction to the class Registration

2 28.02 Exploring MATLAB Assignment 1

3 07.03 Arrays and Matrix Operations N.A.

4 14.03 Arrays and Matrix Operations Assignment 2

5 21.03 Arrays and Matrix Operations Assignment 3

6 28.03 Polynomials and curve-fitting Assignment 4

7 04.04 Descriptive statistics Assignment 5

8 11.04 Programming Elements of MATLAB N.A.

9 18.04 Programming Elements of MATLAB Assignment 6

10 25.04 Programming Elements of MATLAB Assignment 7

11 02.05 Plotting and Animations N.A.

12 09.05 Plotting and Animations Assignment 8

13 16.05 Numerical Integration Assignment 9

14 23.05 Symbolic Math Assignment 10

15 30.05 Take-home final project N.A.

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See you next week!

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