How do I iterate over vector elements, but ignore elements which do not meet a condition?
6 visualizzazioni (ultimi 30 giorni)
Mostra commenti meno recenti
Daniel Pollard
il 11 Dic 2020
Commentato: Daniel Pollard
il 11 Dic 2020
I have a piece of code, which I'm trying to make run faster. I've used the profiler and most of the time is spent on the following snippet:
for det = 1:N
if detect_vec(det)
result((det+1):(det+deadTime), m0, h) = zeros([1, deadTime]);
end
end
What this is doing is iterating over an array detect_vec which is binary data - each element is a 1 or a 0. If there is a 1, it then sets any other 1s following it to 0. deadTime is a variable which defines how many values after a 1 should be set to 0.
I'm sure there must be a way to make this more efficient; N is very large and so it makes sense that the profiler says the code spends most of its time here. I've tried using the find function by doing the following;
for det = find(detect_vec)
if detect_vec(det)
result((det+1):(det+deadTime), m0, h) = zeros([1, deadTime]);
end
end
This code runs without error but returns many more 1s than I'm expecting, and isn't really any quicker.
Any advice would be great.
4 Commenti
dpb
il 11 Dic 2020
Unless the separation of elements in detect_vec is >deadTime you'll be resetting elements multiple times and moving the location of the string of zeros along with it.
Is this intended behavior? You could otherwise increment by the gap at least. Whether this reduces iterations or not would depend on the relative values and number of detection locations.
You may want to look at fillmissing with the 'MaxGap' option (if you have R2020b, I think is required).
Risposta accettata
Più risposte (2)
Matt J
il 11 Dic 2020
Modificato: Matt J
il 11 Dic 2020
e=zeros(1,deadTime);
I=conv( double(detect_vec~=0), [e+1,0,e] , 'same')>0;
result(I, m0, h)=0;
2 Commenti
Matt J
il 11 Dic 2020
Maybe use FFTs to do the convolution, or maybe,
e=ones(1,deadTime);
I=conv( double(detect_vec~=0), [e,0] , 'same')>0;
result(I, m0, h)=0;
Vedere anche
Categorie
Scopri di più su Operating on Diagonal Matrices in Help Center e File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!