How do I put peaks, prominences, widths and location in an array

Hi everyone!

Below is my code and I am try to incorporate the function findpeaks(y,'MinPeakProminence',0.1,) it almost works but the only problem is I get errors every time I try to put the minimum peak prominences into the arrays all peaks and findpeaks(y).

If anyone knows how to fix this I'd again be grateful!

fieldNames = fieldnames(MCR_full.MIB037.Reaches);

allPeaks = cell(10,1);

for k = 1 : 10

for k = 1 : 10

thisFieldName = fieldNames{k};

thisArray = MCR_full.MIB037.Reaches.(thisFieldName).kin;

x = thisArray(:, 1);

y = thisArray(:, 3);

[pks,locs,widths,proms] = findpeaks(y);

allPeaks{k} = findpeaks(y);

reachLimitArray= findpeaks(y,'MinPeakProminence',0.1)

if length(reachLimitArray )> 1

disp('There is at least two value above the limit.');

for i = 1 : length(reachLimitArray)

prominence= reachLimitArray(i);

disp(peaks(prominence));

end

else

disp('All values are below the limit.');

end

celldisp(allPeaks)

end

end

Error: Array indices must be positive integers or logical values.

[KALYAN ACHARJYA]

Which line (error)?

[Mackenzie Maher]

That’s what I’m trying to figure out. When I run each line separately, I can’t find the error but when I run the entire thing I get the error message below

 Array indices must be positive integers or logical values.

It doesn’t say what line though

[Voss]

My guess would be this line:

   disp(peaks(prominence));

[Mackenzie Maher]

Can you not do that or did I just format it wrong?

Answer 1

[Star Strider]

Since ‘prominence’ is the first output of that particular findpeaks call, it has the values of the peaks, not their locations (the second output, that would be integer subscript references), so unless the peak values are all integers greater than 0 and are within the number of elements of ‘peaks’ (extremely unlikely in my experience) they are going to be non-integers and will throw that error.

[Mackenzie Maher]

So if I called it (index) and not (prominence)) would that work?

[Star Strider]

So long is it consists of integers that are all within the number of elements of the vector it’s indexing, you can call it anything you want!

[Mackenzie Maher]

So how do i create an array that has the prominences I want without having too many input arguments?

[Star Strider]

You essentially already did that with —

[pks,locs,widths,proms] = findpeaks(y);

You can then use ‘logical indexing’ (see the documentation on Matrix Indexing for details) to extract the corresponding values from the other vectors.

Example —

idx = proms >= 0.1; % Logical Index Of Prominences Meeting Requirements

pksDesired = pks(idx)

locsDesired = locs(idx)

widthsDesired = widths(idx)

promsDesired = proms(idx)

All the selected values will correspond to each other.

Experiment with this approach to get the desired results.

[Mackenzie Maher]

Thanks so much!

[Star Strider]

As always, my pleasure!

.