I had asked for an explanation for 2 codes before this. This algorithm compares the previous two. Can I get a step by step explanation as to how this works? I'd really appreciate any help.

Comparison of Efficiency in Terms of Reduction:

function [G]= compare(A)

G=cell(1,9);

[U S V]=svd(A);                   %calling built-in SVD
G{1,1}=S;
Ts=trace(S);                      %sum of diag elements of S
[Vj,D]=JacobiEig(A);               %calling Jacobi SVD method from the same directory
G{1,2}=D;
Tj=trace(D);                      %sum of diag elements of D
[Z PCred Vp Di] = pca1(A);         %calling PCA method from the same directory
G{1,3}=Di;
Tp=trace(Di);                     %sum of diag elements of Di

if Ts < Tj
    disp('SVD is lighter in magnitude than Jacobi SVD');
    if Ts < Tp
       disp('SVD is lighter in magnitude than PCA');
    else
       disp('PCA is lighter in magnitude than SVD'); 
    end
else
    disp('Jacobi SVD is lighter in magnitude than SVD');
    if Tj < Tp
       disp('Jacobi SVD is lighter in magnitude than PCA');
    else
       disp('PCA is lighter in magnitude than Jacobi SVD'); 
    end
end

[K,m,L,n] = Compress(S,D);
[Mj,Ms] = Recon(K,m,L,n,Vj,S,V,U);

G{1,4}=K;
G{1,5}=Mj;
G{1,6}=PCred;
G{1,7}=Z;
G{1,8}=L;
G{1,9}=Ms;

end