How to use parfor to make a new matrix form an existing one

Hi. I have a matrix A which is used to generate a new matrix B within loops. I used parfor to do this but it is not working. Could you please someone let me know how I can modify the code to make use of parfor. The code is as follows:

    n_c=8;    
    n_c1=n_c+1;  
    L=2*(n_c1);
    h=size(A);
    h1=h(1);    
    nn_1=n-1; nn_2=2*n-2;    
    s2=2*n;
    L_1=L-2:    
    for a=0:1
        for b=0:1
            if n<=n_c1
                B=zeros(h1,s2);
                parfor i=1:h1                    
                    B(i,1:s2)=[a,A(i,1:nn_1),b,A(i,n:nn_2)];                    
                end
            else                
                B=zeros(h1,L); 
                parfor i=1:h1                    
                    B(i,1:L)=[a,A(i,1:n_c),b,A(i,n_c1:L-2)];                    
                end
            end
        end
    end   

This code is inside a bigger loop with the counter n.

Thank you very much

Answer 1

[Walter Roberson]

In both cases, you are assigning to an entire column of B. Skip the 1:s2 or 1:L indexing: they are confusing parfor. Just assign to B(i,:)

But remember your code is going to create a completely new B matrix for each iteration of a and b, so you might as well only do the last a and last b since you are overwriting all of B each time.