Vectorization of nested for loop

Hello,

I am trying to vectorise a piece of code. The code is the following:

main_calc=zeros(N,length(time));                                %initialize main calculation
for wall_send=1:length(6)                                       %sending wall
    for send=1+lenght(wall_send):lenght(wall_send+1)            %elements on the sending wall
        for wall_rec=1:length(6)                                %receiving wall
            for rec=1+lenght(wall_send):length(wall_send+1)     %elements of receiving wall
                main_calc(rec,time_step_ij)=main_calc(rec,time_step_ij)+previous_calc(send,time_step_ij);   %new calc
            end
        end
    end        
end      
previous_calc=main_calc; %update

How do I vectorize the above code?

Thank you

[Rena Berman]

(Answers Dev) Restored edit

Answer 1

[Sulaymon Eshkabilov]

I don't think what you are doing is a vectorization. Here is a simple demo of vectorization :

% Loop
x = linspace(0, 2*pi);
y = linspace(-pi, pi);
Z = zeros(numel(x), numel(y));
for ii = 1:numel(x)
    for jj=1:numel(y)
        Z(ii,jj) = sin(x(ii))+cos(y(jj));
    end
end
figure(1)
mesh(Z)
title('Computed with a loop')

% Vectorization
x = linspace(0, 2*pi);
y = linspace(-pi, pi);
[X, Y] = meshgrid(x,y);
Z = sin(X)+cos(Y);
figure(2)
mesh(Z')
title('Computed with a vectorization')

[Ilaria]

i am not sure this does help me. What should I do in my case?