Matlab Code for Circular Convolution using Matrix Method and also not using cconv method

Matlab Code: 

clc;

clear all;

close all;

%Circular Convolution by Matrix Method

x=input('Enter the first sequence: ');

h=input('Enter the second sequence: ');

n=max(length(h),length(x));

A=0;

%To obtain a circular matrix

for i=1:n

    if i==1

        for j=1:n

            A(i,j)=x(j); %first row stores all the elements of x(n)

        end

    else

    for j=1:n

        if(j==1)

            A(i,j)=x(n-i+2); %first column of rows from i=2 to n are x(n),

                                                                               x(n-i+2),...,x(3),x(2)

        else

            A(i,j)=A(i-1,j-1); % the last (n-1) elements of present row is the 

                                                    fist (n-1) elements of the previous row 

        end

    end

    end

end

disp(A);

X=A*h';  %To calculate matrix multiplication

disp("Circular Convolution by Matrix Method:");

disp(X');

%Calculating Circular Convolution with out using cconv function

disp('Without using cconv method, circular convolution is: ');

l1=length(x);

l2=length(h);

x=[x zeros(1,n-l1)];

h=[h zeros(1,n-l2)];

y=zeros(1,n);

for i=1:n

    for j=1:n

        k=mod(i-j,n);

        k=k+1;

        y(i)=y(i)+x(j)*h(k);

    end

end

disp(y);

%Calculating Circular Convolution using cconv() method

disp("By formula:");

Z=cconv(x,h,n);

disp(Z);

Output:

Enter the first sequence: [1 2 1 2]

Enter the second sequence: [4 3 2 1]

     1     2     1     2

     2     1     2     1

     1     2     1     2

     2     1     2     1

Circular Convolution by Matrix Method:

    14    16    14    16

Without using cconv method, circular convolution is: 

    14    16    14    16

By formula:

    14    16    14    16