MATLAB: Problem in applying loop

Question

I have emg signal (30000×4) and want to apply function on it in loop….

function waveLen = find_waveform_length(signal)

sum=0;

for i=2:length(signal)

sum= sum + abs(signal(i)-signal(i-1));

end

waveLen = sum;

%%%%%% New file %%%%%%%

load ('dath001.mat');

x = dath001; % 30000×4

for i = 1:4

waveLen(i) = find_waveform_length(x(i))

end

but it give output of 0 0 0 0

instead if i run waveLen function separately it give output of

463.6428 200.0671 411.7511 372.9306 … I want this output by simple apply loop command

Thank you

Answer 1

What is the 'y' you have used in your main script loop? Its not defined anywhere. Use this line in main script:

waveLen(i) = find_waveform_length(x(:,i))

Since you have not shared your MAT file, I tried with a random 30000x4 matrix and it works.

Few other recommendations:

1) Put an 'end' for your function

2) Don't use variable 'i' or any other inbuilt Matlab variable as index in your 'for' loop.