How to to find the singular value (sigma) in image compression in SVD without using built in command?

 I have already find the matrix 80X80, but i want in matrix 99X80. In file that i have attach, i used sigma=sqrt(Q). 

 %reading and converting the image
A=imread('C:\Users\SONY\Documents\project mat723\echaphoto1.jpg');
A=rgb2gray(A);
B=double(A); %transform to real values
S=B(:,:,1);  %convert B to matrix form
C=transpose(B);
D=C*B;%(A^t)*A
K=im2double(D);
y=poly(D);  %characteristic polynomial
P=roots(y);  %eigenvalues,(lambda)
[V,e]=eig(D);
V1=V(:,:,1); %eigenvector for matrix D
[m,n]=size(B);
Q=zeros(m,n);
R=zeros(n,n);
for j=1:80
    v=B(:,j);
    for i=1:j-1
        R(i,j)=Q(:,i)'*B(:,j);
        v=v-R(i,j)*Q(:,i);
    end
    R(j,j)=norm(v);
    Q(:,j)=v/R(j,j);  %normalize v to be the next unit vector
end
sigma=sqrt(e);
%W=orth(Q)
[W,M]=qr(Q);
s=svds(sigma);
VT=transpose(Q);
Y=rand(m,n);
I=eye(n);
Z=complex(Y,B);

[Jan]

Please format your code properly (see the "{} Code" button) and omit the brute but useless clear all.

[Erni Suryani]

I have already edit my code properly. Can you help me?