# Vectorization of Loops with Matrix Multiplications

5 views (last 30 days)
Tommaso Belluzzo on 30 Mar 2020
Answered: Matt Shellhammer on 31 Mar 2020
Hi all. I have the following code which is being repeated many times with different time series and this is producing a huge bottleneck on my code:
%% Example Data
t = 252;
h = randn(252,2);
l = round(0.1 * t,0);
%% Loop
for i = 1:(l - 1)
o_tmp = h(1,:).' * h(1+i,:);
for j = 2:(t - i)
o_tmp = o_tmp + h(j,:).' * h(j+i,:);
end
o_tmp = o_tmp / (t - i);
end
I would like ti know if there is a suitable way to improve it, maybe by vectorizing all computations or just some of them. Any suggestion is more than welcome. Thanks in advance for your help!
David Hill on 30 Mar 2020
It would help if you explained what you are trying to do (big picture).

Matt Shellhammer on 31 Mar 2020
%% Example Data
t = 252;
h = randn(252,2);
l = round(0.1 * t,0);
%% Loop
for i = 1:(l - 1)
o_tmp = (h(1:(t-i),:).' * h((1+i):t,:))/(t-i);
end

R2018a

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