# Can this for loop be vectorized?

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Snoopy on 28 Feb 2022
Edited: Bruno Luong on 1 Mar 2022
The for loop below runs over the third dimension (page) to fill the alpha array. Is it possible to vectorize this for loop?
alpha_i_h_t = NaN(N_i,N_t,N_draws);
for i = 1:N_draws
alpha_i_h_t(:,:,i) = e_i_h(:,i) + e_h * t;
end
Torsten on 28 Feb 2022
e_i_h(:,i) is a column vector. For e_i_h(:,i) + e_h * t to be defined, e_h * t must be a column vector or a scalar.
So how do you want to write a column vector into a matrix array alpha_i_h_t(:,:,i) ?
Bruno Luong on 28 Feb 2022
No Torsen because MATLAB auto-expansion.

Bruno Luong on 28 Feb 2022
Edited: Bruno Luong on 28 Feb 2022
e_i_h_reshape = reshape(e_i_h,N_i,1,N_draws);
alpha_i_h_t = e_i_h_reshape + e_h * t;
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Torsten on 28 Feb 2022
And why do you need a three-dimensional array for a two-dimensional content ?
Or do I get something wrong ?
Bruno Luong on 1 Mar 2022
Edited: Bruno Luong on 1 Mar 2022
The result is 3D, each page contains a matrix sum of column by row vector.