increase processing speed of code entropy histcount

Question

ALDO 2021-7-27

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/887104-increase-processing-speed-of-code-entropy-histcount

评论： ALDO 2021-8-3

Hi

I have the following code and an trying to calculate entropy of a signal over a moving window. my signal is A=1x1080000. sampling frequency is 125 samples/sec. Please find my code below.

I know my code is correct because it gives me the correct answer when i choose a large window and large shift value. but it take very long to process when the window and shift size are smaller. Does any One have any suggestions on how to optimize it so that it would run faster. Thank you in advance for your help. Please ley me know if anything is unclear.

Best regards,

windowsize=2*125; % 2second window taking into account sampling frequency

shiftsize=floor(1*125);

initial = 1:shiftsize:length(A);

final = windowsize:shiftsize:length(A);

for j=1:length(final)

B=A(initial(j):final(j));

pdf=histcounts(B,'Normalization', 'pdf');

app.entropyA(final) = -sum(pdf.*log2(pdf));

end