Find peaks in a for loop?

i have a 1007x94 matrix, how would I write a for loop to find the peak in every row?

Answer 1

[Star Strider]

The maxk and mink functions (introduced in R2017b) would make this a bit more efficient. Lacking them, use sort.

Try this —

A = randn(1007, 94);
for k = 1:size(A,2)
    [pks, locs] = findpeaks(A(:,k));
    [~,ix] = sort(pks);
    minpk{:,k} = [pks(ix(1:2)) locs(ix(1:2))];
    maxpk{:,k} = [pks(ix(end-1:end)) locs(ix(end-1:end))];
end

maxpk{1}                                                        % View Result

ans = 2×2

3.0201 816.0000 3.3828 355.0000

minpk{1}                                                        % View Result

ans = 2×2

-1.0253 384.0000 -0.9567 702.0000

.

Answer 2

[Vasudev Sridhar]

Assuming you mean maximum when you say peak.

a = randi(20, 2,10)

a = 2×10

15 18 17 14 2 6 17 1 7 9 6 17 18 18 4 5 17 19 1 18

result = max(a,[],2)

result = 2×1

18 19

[Troth]

My goal is to write a loop to find the 2 highest peaks and two lowest of each column (not row I made a mistake) and each index which it occurs, but to use the find peaks function to do so.