Programming with matlab session 1

INTRODUCTION
to
MATLAB
By: Prof. Ganesh Ingle

Session objective
COMPUTERS AND PROGRAMMING
PROGRAMMING LANGUAGES TYPES
MATLAB INTRODUCTION
IDE ,COMMANDS ,RESULTS ,M FILE
COMPARE A SAMPLE CODE IN C WITH MATLAB
SUMMARY

Computers and Programming
1. Computer: An electronic device which
is capable of performing complex
arithmetical and logical operations to
get the desired result
2. Program: Set of instructions given to
the computer to execute a particular
task.

Programming Languages Types
1. Machine level language
2. Assembly level language (Assembler)
3. High level language (Compiler interpreter)

MATLAB Introduction
1. What is MATLAB ???
2. Why MATALB???
a. Interfacing API for
TMS320(DSP),ARM,89s51,89s52,…..
b. Port interfacing
c. Reduces time required for PDLC
d. Scientific calculations

MATLAB Applications
1. Communication engineering
2. AI,ML,DL
3. Image processing
4. Optimization
5. Data access ,analysis and visualization
6. Programming and algorithm designing
7. Performance analysis of algorithms
8. Simulink

MATLAB Commands
1. date
2. clock
3. ver
4. whos
5. what(files in current dir)
6. clc
7. clear
8. diary filename
9. diary off
10. diary on
11. path
12. editpath GUI ,home,set path
13.! DOS command
14. exit

MATLAB Operators/Symbols/Functions
1. +
2. -
3. *
4. /
5. ^
6. =
7. ==
8. pi
9. vpa (digit precision)
10. %
11. ;
12. : range
13.randn() %10,
1:1:10;
14. Ctrl+c
15. ceil
16. floor
17. sqrt
18. Matrix (+,-,*)
19. ‘.’ operator
20. eye
21. zeros(5)
22. ` transpose
23. ones(6)

24. imread()
25. imshow
26. disp()
27. input()
28. factorial()
29. length(a)
30. size(a)
31. fprintf()-only o/p
32. sprintf()-o/p with save in workspace
33. format rat/ long /hex /shortEng/logEng
34. de2bi, d=(1:10)’; b=de2bi(d); [d,b]
35. decimalToBinaryVector(x);MSB,LSB

36. All trigonometric values and error o/p
37. cosd(),sind()
38. All hyperbolic trigonometric values
39. mod(x,y)
40. log(x) %natural log
41. log10(x)

MATLAB Variables and Data Types
Data types
Logical Char Numeric
Int 8 unint 8
Int 16 unint 16
Int 32 unint 32
Int 64 unint 64
Single Double
Structure Function Handle

Typing Mathematical Expression
1)
R1=
−𝑏+ 𝑏2−4𝑎𝑐
2𝑎
R2=
−𝑏± 𝑏
2
−4𝑎𝑐
2𝑎
2)
R1= 𝑎2 + 𝑏2
e-0.2t cos 2t
3)
E=mc2
Y=1 +
𝑛𝑥
1!
+
𝑛 𝑛−1 𝑥2
2!

MATLAB Code File
1. File name should not start with number
2. No Space in the file name
3. No library function name
4. No use of keywords reserved by MATALAB
MATLAB Searching Mechanism
1. Workspace
2. Current directory
3. Set path directory

Compare code in C with MATLAB
1. WAP program to perform addition of two
numbers a and b with following constraint:
 Do not use + operator i.e. c=a+b
 Do not use –(-) operator i.e. c=a-(-b)
 Do not use x(-1) i.e. c=a-b(-1)
 Do not use c=b-(-a)
 Do not c=b-(-a)
 Do not use c=a-
𝟏
𝟏
−𝒃
 Do not use c=b-
𝟏
𝟏
−𝒂
 Do not use c=
𝒂 𝟐−𝒃 𝟐
𝒂−𝒃
Objectives:
1. Find the solution and
logic
2. Compare C and Matlab
code

MATLAB Programming Exercise
1. WAP to find the roots of the quadratic
equations
2. Ideal gas law problem to find volume
3. Let us see direct implementation using
MATLAB………..

THANK YOU
Image Source
searchenterpriseai.techtarget.com
wikipedia

%Matrix computations and operations
>> %creating vectors and matrices
>> %create a row vector, we can form a row vector.
>> a=[1 3 6 8];
>> a
a =
1 3 6 8
MATLAB Command With Syntax

>> %create a column vector,
>> b=[1;4;6;10];
>> b
b =
1
4
6
10

>>Create the matrix x of 3 rows and 4 columns
x=[12 23 21 3; 2 34 5 7; 31 32 33 34];
>> x
x =
12 23 21 3
2 34 5 7
31 32 33 34

%elements of a Matrix
>> z=x(2,3)
z = 5
>> x1=x(1,:)
x1 = 12 23 21 3
>> x2=x(:,2)
x2 =
23
34
32
>> s=size(x)
s = 3 4

Remove the n th
X(n, : ) = [ ]
x(2, : ) = [ ]
Add a column of 4,s to the end of matrix.
x( ; , 4) = 4

We can extend the colon notation to specify a
sequence
Create a vector v which starts at 1, with increment
of 2 and stops at 10:
v=1:2:10
v = 1 3 5 7 9
>> v=1:10
v = 1 2 3 4 5 6 7 8 9 10

x=[11 12 13 14; 21 22 23 24;31 32 33 34];
>> x
x =
11 12 13 14
21 22 23 24
31 32 33 34
We can use this vector notation when
referring to sub matrix:
w=x(1:2:3, 2:4)

w =
12 13 14
32 33 34
Rows :start at 1, increment by 2, stop at 3
Columns 2,3,4start at 2, stop at 4 default
increment of 1 is used

x=[11 12 13 14;21 22 23 24 ;31 32 33 34 ]
x =
11 12 13 14
21 22 23 24
31 32 33 34
>> x4=x(1:2:3,2:4)
x4 =
12 13 14
32 33 34

x4=x(1:2:2,2:4)
x4 =
12 13 14
>> x4=x(1:1:3,2:4)
x4 =
12 13 14
22 23 24
32 33 34

x4=x(1:1:2,2:4)
x4 =
12 13 14
22 23 24
x4=[x;41 42 43 44]
x4 =
11 12 13 14
21 22 23 24
31 32 33 34
41 42 43 44
x= [41 42 43 44;x] ?

x4 = x(2:1:3,2:4)
x4 =
22 23 24
32 33 34
x(4 , : ) = [41 42 43 44]
x =
11 12 13 14
21 22 23 24
31 32 33 34
41 42 43 44

x4=x(1:1:2,1:4)
x4 =
11 12 13 14
21 22 23 24
>> x4=x(1:1:2,2:4)
x4 =
12 13 14
22 23 24
>> x4=x(1:1:2,3:4)
x4 =
13 14
23 24

Strings
String handling
Syntax
S = 'Any Characters'
S = [S1 S2 ...]
S = strcat(S1, S2, ...)

Examples
Create a simple string that includes a single quote.
msg = 'You''re right!'
msg =
You're right!
Create the string name using two methods of
concatenation.
name = ['Thomas' ' R. ' 'Lee']
name = strcat('Thomas',' R.',' Lee')

Create a vertical array of strings.
C = strvcat('Hello','Yes','No','Goodbye‘)
C =
Hello
Yes
No
Goodbye

S = {'Hello' 'Yes' 'No' 'Goodbye'}
S =
'Hello' 'Yes' 'No' 'Goodbye'
Create a cell array of strings.
S = {'Hello' 'Yes' 'No' 'Goodbye}

1. Commands for Managing a Session
2. MATLAB provides various commands for managing a session.
3. The following table provides all such commands −
4. I have forgotten the Variables!
5. The who command displays all the variable names you have
used.
6. who
7. MATLAB will execute the above statement and return the
following result

>> who
Your variables are:
a b x
>> whos
Name Size Bytes Class Attributes
a 1x4 32 double
b 4x1 32 double
x 3x4 96 double

whos
Name Size Bytes Class Attributes
a 1x4 32 double
b 4x1 32 double
x 3x4 96 double

Basic Task: Plot the function sin(x) between 0≤x≤4π
 Create an x-array of 100 samples between 0 and 4π.
 Calculate sin(.) of the x-array
 Plot the y-array
>>x=linspace(0,4*pi,100);
>>y=sin(x);
>>plot(y)
0 10 20 30 40 50 60 70 80 90 100
-1
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1

Plot the function e-x/3sin(x) between 0≤x≤4π
 Create an x-array of 100 samples between 0 and 4π.
 Calculate sin(.) of the x-array
 Calculate e-x/3 of the x-array
 Multiply the arrays y and y1
>>y=sin(x);
>>y1=exp(-x/3);
>>y2=y.*y1;

Plot the function e-x/3sin(x) between 0≤x≤4π
 Multiply the arrays y and y1 correctly
 Plot the y2-array
>>y2=y.*y1;
>>plot(y2)
0 10 20 30 40 50 60 70 80 90 100
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7

Display Facilities
 plot(.)
 stem(.)
Example:
>>y=sin(x);
>>plot(y)
>>plot(x,y)
Example:
>>stem(y)
>>stem(x,y)
0 10 20 30 40 50 60 70 80 90 100
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0 10 20 30 40 50 60 70 80 90 100
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7

Display Facilities
 title(.)
 xlabel(.)
 ylabel(.)
>>title(‘This is the sinus function’)
>>xlabel(‘x (secs)’)
>>ylabel(‘sin(x)’)
0 10 20 30 40 50 60 70 80 90 100
-1
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
This is the sinus function
x (secs)
sin(x)

Operators (relational, logical)
 == Equal to
 ~= Not equal to
 < Strictly smaller
 > Strictly greater
 <= Smaller than or equal to
 >= Greater than equal to
 & And operator
 | Or operator
 ~ NOT

Name Meaning
ans Most recent answer.
eps Accuracy of floating-point precision.
i,j The imaginary unit √-1.
Inf Infinity.
NaN Undefined numerical result (not a
number).
pi The number π
Special Variables and Constants
MATLAB supports the following special variables and constants:

Multiple Assignments
You can have multiple assignments on the same
line.
For example,
a = 2; b = 7; c = a * b
MATLAB will execute the above statement and
return the following result −
c = 14

The clear command deletes all (or the specified)
variable(s) from the memory.
clear x % it will delete x, won't display anything
clear % it will delete all variables in the
% workspace
% peacefully and unobtrusively

Command Purpose
clc Clears command window.
clear Removes variables from memory.
exist Checks for existence of file or variable.
global Declares variables to be global.
help Searches for a help topic.
lookfor Searches help entries for a keyword.
quit Stops MATLAB.
who Lists current variables.
whos Lists current variables (long display).
Commands for Managing a Session
MATLAB provides various commands for managing a session.
The following table provides all such commands −

MATLAB provides various useful commands for
working with the system, like saving the current work
in the workspace as a file and loading the file later.
It also provides various commands for other system-
related activities like, displaying date, listing files in
the directory, displaying current directory, etc.

Command Purpose
cd Changes current directory.
date Displays current date.
delete Deletes a file.
diary Switches on/off diary file recording
Commands for Working with the System
The following table displays some commonly used system-related commands −

Command Purpose
disp Displays contents of an array or string.
fscanf Read formatted data from a file.
format Controls screen-display format.
fprintf Performs formatted writes to screen or file.
input Displays prompts and waits for input.
; Suppresses screen printing.
Input and Output Commands
MATLAB provides the following
Input and output related commands −

Assignments
1. Create a matrix A of zeros [2x4], and B of ones[2x3].
i. Add A by 2 to create matrix of twos.
ii. Can we add A+B? and A-B? justify your Answer.
2. Create matrix of 4 rows and 3 columns.
i. Add X by 4 to create new matrix called Y.
ii. Form C= X+Y
iii. Form D= X-Y
iv. Remove second row.
v. Add a column of 4’s to the end of matrix.
3. Using matrix operations to solve the following system of linear equations.
4x - 2y + 6z = 8
2x + 8y + 2z = 4
6x +10y +3z = 0.

Programming with matlab session 1

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