How to speed up for loop with if condition

Question

Nicolò Monaco 2022-3-17

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1674179-how-to-speed-up-for-loop-with-if-condition

回答： M.B 2022-3-18

Hello. I have the following code:

tilt = zeros(length(delta_tilt),width(delta_tilt));
for k= 1:(length(delta_tilt)-1)     
    tilt(k+1,:)= tilt(k,:)+delta_tilt(k+1,:);  
    for i= 1:365
        if tilt(k+1,i)>constraint_up;
            tilt(k+1,i)= constraint_up;
        elseif tilt(k+1,i)<constraint_down;
            tilt(k+1,i)= constraint_down;
        end 
    end 
end

Considering delta_tilt an array 86400*365, computational time for this operation results very heavy. There's any way to speed up this operation?

I want to build "tilt" as the cumsum of delta_tilt, but if the value k of tilt is out of boundaries, I want that the value k+1 takes in consideration this limitation.

Thanks in advance.

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Answer 1

M.B 2022-3-18

1
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https://ww2.mathworks.cn/matlabcentral/answers/1674179-how-to-speed-up-for-loop-with-if-condition#answer_920809

在 MATLAB Online 中打开

Not sure if it speeds up the code, but you can try the following:

tilt = 0*delta_tilt;
for k = 1:(size(delta_tilt, 1)-1)    
    tilt(k+1,:)= tilt(k,:)+delta_tilt(k+1,:);  
    tilt(k+1,:)= min(tilt(k+1,:),constraint_up);
    tilt(k+1,:)= max(tilt(k+1,:),constraint_down);
end