fun applied to a loop

Hi, I am struggling to apply my fun to a loop. Any tip? Here is my code:

       function T=totalflow(x,N)
                T(:)=x(1:N)+x(N+1:2*N);
       end
       %saved as totalflow.m

and main program:

    inFlow = rand(10,3);
    x0 = [inFlow; zeros(size(inFlow))];
    [N,M] = size(inFlow);
    T=totalflow(x0,N);
    % this works for only one column on inFlow. I want to get T[10,3] like:
    for i=1:M
        T(:,i)=totalflow(x0(:,i),N);
    end 
    %this does not work. Any tip? Thanks

Answer 1

[Stephen23]

function out = totalflow(x,N)
out = x(1:N) + x(N+1:2*N);
end

and

M = rand(10,3);
[R,C] = size(M);
T = nan(R,C);
X = [M;zeros(R,C)];
for k = 1:C
    T(:,k) = totalflow(X(:,k),R);
end

[sensation]

Thanks! So the trick was in preallocating:) I used T = zeros([R,C]); instead of T = nan(R,C). The second did not run on my matlab version (2016a). Thanks!

Cheers

Answer 2

[Torsten]

Use

% T=totalflow(x0,N);

instead of

T=totalflow(x0,N);

Best wishes

Torsten.