Matlab Basic Part 2

Matlab Basic Part 2

In the first Part We See Some Basic of Matlab. now in the Part 2we will see some advanced functions and methods of Matlab. then we go forward to our work on the Telecom And Networking side. In this section we will see about the loop statements and how to draw plots figure etc. 

if, if else, else Statement in Matlab

>> A=109;

>> B=104;

>> If (A > B)

>> fprintf('A is Greater than B');

>> elseif (A < B)

>> fprintf('B is greater than A');

>> elseif (A = = B)

>> fprintf('B is equal with A');

>> else 

>> fprintf('Unexpected situation');

>> end

In Matlab, loops can be implemented with a for ...end construct or a while ...end construct. In terms of their ability to repeat a series of calculations, for loops and while loops are equivalent.

for Loops

for loops are often used when a sequence of operations is to be performed a predetermined number of times. For example computing the Maximum or Minimum of a list of numbers.

Syntax

Loop counter incremented by one:

for i = startingValue : endingValue

x = Some Value

y = Some value

Do somthing

...

...

...

end

Exp1: Compute the sum of the fi rst n integers

>> n = 10; 

>> sum = 0;

>> for i = 1 : n

>> sum = sum + i;

>> end

Exp2: Compute the average of a list of numbers

>> n = 500;

>> x = rand(1,n);                      % generate a row vector of pseudo random number having length n

>> sum = 0;

>> for i=1:n

>> sum = sum + x(i);                % Add ith element of x to sum

>> end

>> avg = sum/n;

while loop

While Loop is same as for loop, only the difference is it first check the condition then do action. syntax is below

while(condition)

...

...

do something

...

...

end

Switch Statement

In Matlab switch statement is same as other languages like C/C++. but in Matlab no parenthesis are used. the syntax is below:

switch(y)

     case(1)

           do something

           break

     case (2)

          do something

          break

     ...

     ... 

     ...

     case(n)

          do something

          break

     default

          display default message/ do default work

end

Graphics

Graphics are used to see the graphical representation of a sequence/ signal etc. In Matlab two major types of plot are used. one is "plot" command used for continuous signal, second is "stem" command for discrete type signal.

"subplot" command is used if one want to display multipull plots in one figure at different location. if one wants to display one plot together with another plot the after first plot "hold on" command is used. Remember that "figure" command is used to create one figure. 

Exp 3: sine generation: A*sin(omega*n+theta)

>> n = 0: 1: 50;

>> A = 0.87;                                         % Amplitude of sin wave

>> theta = 0.4;                                      % Phase of sin wave

>> omega = 2*pi / 20;                           % frequency of sin wave

>> xn1 = A*sin(omega*n+theta);          % sin generation

>> figure (1);                                         % create first figure

>> subplot(2,1,1);                                 % there are two locations for plot in figure 1

>> plot(xn1);

>> title('first signal');

>> xn2 = A.^n;                                     % exp generation

>> subplot(2,1,2);                                 % xn2 will be plot on the 2nd row 1st column

>> plot(xn2);

>> title('Exponential signal');

>> figure (2);

>> plot(xn1);

>> hold on;

>> plot(xn2);

>> hold off;

>> figure (3);

>> stem (n, xn1);