MATLAB Onramp: Report
Professor: Dr. Rajesh Kandala – NVPS SENSE
Lab slot: L55+L56; CB-101
Student Name: Dev Kumar
Reg. No.: 22BCE9115
What is MATLAB?
MATLAB is a programming and numeric computing
platform that is used by millions of engineers and
scientists to analyse data, develop algorithms, and
create models
MATLAB stands for MATrix LABoratory.
A visual representation of how a MATLAB editor screen looks.
Entering Commands in MATLAB:
In MATLAB, commands can be executed by typing them
in the command window after the prompt “>>” and
pressing enter key.
Unless a variable is specified, The output is stored
under the variable named “ans”.
When you enter a command without semicolon in
MATLAB, The result is displayed, Optionally you can
add a semicolon at the end of a command so that the
value is stored but the result is not displayed.
For example:
K = 8 – 2;
Here the output won’t be displayed.
Previous commands can be recalled using the “up
arrow” - ⬆️ on the keyboard.
When you enter just a variable name in the command
prompt, MATLAB displays the current value of that
variable.
Variables:
In MATLAB, variables can be named anything as long
as they start with a letter and contains only letters,
numbers and underscores.
All the variables get saved in the column on the righthand side of the screen called the workspace.
In order to save all those variables a mat file can be
created with the following command and format:
>>save <filename>.mat
For example:
>>save datafile.mat
This command saves all the variables in the workspace
in a file named “datafile.mat”.
To clear the workspace or delete all the variables from
the work space:
>>clear
The “clear” command gets rid of all the variables
stored in the workspace.
To load our saved “.mat” file with all the variables in
it the command:
>>load <filename>.mat
The command “load <filename>.mat”, loads all the
variables stored in the file into our workspace which
can be then used in our program.
For example:
>>load datafile.mat
The above command loads the variables stored in the
file named datafile. If the file is in a different directory
than our MATLAB program then we need to need to
mention its name along with its path.
Finally, to clear our command window:
>>clc
The “clc” command clears out the command window.
Using built in functions:
MATLAB consists of many built in functions and
constants which can be used to make programs simple
and easy to code.
For example:
Built-in constant
Here “pi” contains the value of mathematical function
pie, where pie = 3.14 or 22/7.
Built-in function
Here the function “sin()” is use to find the sine
function of -5 which is then stored under the variable
“a”.
The MATLAB editor:
MATLAB web editor.
The left grey side of the editor is the part of the
program where we write the code also called the
script, the right panel beside the script is where the
output is displayed.
The bottom window is the command window as it
states.
Lastly on the right pane there is a toggle saying
“workspace”. This toggle opens a slide tab of the
workspace.
Vectors and Matrices:
Arrays:
All MATLAB variables are arrays So, each numeric
variable can contain multiple numbers. You can
store related data in one variable by using an
array.
Creating 1-D arrays:
A single number called a scalar can be represented by
a 1 x 1 array meaning, the array contains 1 row and 1
column.
x = 4;
“x” is a 1 x 1 array. (row x column)
To store more than 1 columns, square braces can be
used to accommodate the extra elements. (row vector)
y = [7 9];
The spaces used here are used to separate the numbers
in their row, a comma(“,”) can be used to do the
same.
Creating multi-Dimensional arrays:
When you separate the numbers in an array using a
semicolon, MATLAB creates a new column vector.
z = [1; 3]
z=
1
3
This array is of an order 2 x 1. (column vector)
Following is a representation of how a matrix would
be constructed in MATLAB:
For long vectors, entering individual numbers is not
practical. An alternative, short hand method to carry
out the same would be using the colon operator,
specifying the start and end values.
For such conditions using the square braces is not
necessary.
For example:
>>g = 5:8
g=
5678
The “:” operator uses a default spacing of 1,
However u can alter it by providing the required
parameter as shown below.
<variable> = <initial>:<increment>:<final>
Syntax
This particular instance uses a spacing of 2 units.
If you know the number of elements you want in a
vector (instead of the spacing between each element),
you can use the “linspace()” function.
>>linspace(<first>,<last>,<number of elements>)
Syntax
To convert a row vector into a column vector, there
exists a transpose operator (‘).
The transpose vector can be used directly to create
column vectors from row vectors.
Similarly, the vice versa is possible.
Creating arrays with functions:
There are many functions in MATLAB which can be
used to generate different types of matrices.
For example:
• rand(n) :- The function rand(n), generates a matrix
of order n x n.
• rand(n, m) :- The function rand(n, m), generates a
matrix of order n x m.
• ones(m, n) :- The function ones(m,n), generates a
matrix of ones of the order of m x n.
And many more such functions exist.
Array indexing and modification:
The data from an array can be extracted using row
and column indexing.
<variable name> = <array>(<row>,<column>)
Syntax
For example:
Y = A (5,6);
In this command, the values of 5th row and 6th column
of the array “A” is stored in “Y”.
To extract only the row or a column, we can just
blank out the unnecessary parameter.
<variable name> = <array>(<row>, )
Syntax
The above syntax fetches only the required row of the
specific array.