% Set T and N
T=1000;
N=10;
% Create some pseudo random numbers
e=randn(T,N);
% Initialize a place for our random walks
rw=zeros(T,N);
% Initialize the recusions
rw(1,:)=e(1,:);
% Loop over t
for t=2:T
    % loop over n
    for n=1:N
        % The actual calculation
        rw(t,n)=rw(t-1,n)+e(t,n);
    end
end
plot(rw)

% Another way that uses one row at a time and avaois the inner loop

rw2=zeros(T,N);
% Initialize the recusions
rw2(1,:)=e(1,:);
% Loop over t
for t=2:T
    % The actual calculation
    rw(t,:)=rw(t-1,:)+e(t,:);
    % Note the use of : to mean all columns
end





% Another way using cumsum
rw3=cumsum(e);

% Make sure they are identical
disp([' The max absolute difference is ' num2str(max(max(abs(rw-rw3))))])