ENG004
ALGORITHMS &
INT. TO PROGRAMMING
Week 3
“An introduction to arrays and matrices”
Ahmet Anıl Dindar
07.03.2007
The class facts
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E-mail address: [email protected]
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Class web page:
http://web.iku.edu.tr/courses/insaat/eng004/
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Last week
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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
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Defining a new variable
Assigning a value to a variable
Variable types
An introduction to arrays and matrices
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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
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What is variable?
Homer Simpson
Are there anyone
whose name is
Homer Simpson?
(probably)
YES
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Variables:
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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 alphanumeric.
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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Variables in MATLAB (Alphabetic):
>> a=1
a=
1
>> a=1
a=
1
>> a+a
ans =
2
>> a=1
a=
1
>> a+a
ans =
2
>> a*a
ans =
1
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Variables in MATLAB (Alphanumeric):
>> a1=10
a1 =
10
>> a1=10
a1 =
10
>> a1
a1 =
10
>> a1=10
a1 =
10
>> a1
a1 =
10
>> a1*(2*a1)/5
ans =
40
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Variables in MATLAB:
>> a=10
a=
10
>> a1=5
a1 =
5
>> a+a1
ans =
15
>> a+a1*(a-a1)
ans =
35
>>
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An introduction to arrays and matrices
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What is matrice?
What is array?
What are the matrices we use?
What are the calculations?
The properties of the matrices?
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The matrices named with variables?
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Creating a Matrice
Row Matrix (Vector)
>> a=[1 3 4]
a=
1 3 4
Column Matrix (Vector)
>> a1 =
1
2
3
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Creating a Matrice
An Ordinary Matrice
>> ali=[1 2 3;4 5 6;7 8 9]
ali =
1 2 3
4 5 6
7 8 9
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Generating arrays and matrices by defining
certain rules:
Generic Creation
(one by one):
>> a=(1:10)
a=
Columns 1 through 7
1 2 3 4 5 6
Columns 8 through 10
8 9 10
Generic Creation
(two by two):
>> deli=(1:2:10)
deli =
1 3 5 7
>>
Generic Creation
(???):
>> deli=(10:-2:0)
deli =
10 8 6 4
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9
2
0
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Generating arrays and matrices by defining
certain rules:
Some Special
Matrices
>> ones(1,10)
ans =
1 1 1
>> zeros(1,5)
ans =
0 0 0
1
1
0
0
1
1
1
1
1
What about a matrice with full of 2’s
>> twos(1,5)
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Generating arrays and matrices by defining
certain rules:
Some Special
Matrices
>> ones(1,10)
ans =
1 1 1
>> zeros(1,5)
ans =
0 0 0
1
1
0
0
1
1
1
1
1
What about a matrice with full of 2’s
>> twos(1,5)
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Creating matrices from matrices
Using matrices to create new matrices
>> a=(1:5)
a=
1 2
>> b=(2:6)
b=
2 3
>> c=[a;b]
c=
1 2
2 3
3
4
5
4
5
6
3
4
4
5
5
6
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Assignment
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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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