How can I get this code to print the "Non-Reversal Filtered Data" graph from a txt file? I get the "Removed No-Reversal Cycles" currently.

% Read data from text file
data = readmatrix('Aero.txt');

% Find the indices of local extrema
[~, locs] = findpeaks(data);
[~, mins] = findpeaks(-data);

% Check if the first extremum is a maximum or a minimum
if locs(1) < mins(1)
    isMax = true;
else
    isMax = false;
end

% Remove no-reversal cycles
if isMax
    for i = 1:length(locs)-2
        if locs(i) > mins(i) && locs(i+1) < mins(i+1)
            continue;
        elseif locs(i) < mins(i) && locs(i+1) > mins(i+1)
            continue;
        else
            data(locs(i):mins(i)) = NaN;
        end
    end
else
    for i = 1:length(mins)-1
        if mins(i) > locs(i) && mins(i+1) < locs(i+1)
            continue;
        elseif mins(i) < locs(i) && mins(i+1) > locs(i+1)
            continue;
        else
            data(mins(i):locs(i)) = NaN;
        end
    end
end

% Remove NaN values
data(isnan(data)) = [];

% Write the modified data to a new text file
dlmwrite('flight_recorded.txt', data, 'delimiter', '\n');

% Read data from text file
data1 = readmatrix('flight_recorded.txt');

% Plot the data
plot(data1);

% Add labels and title
xlabel('Cycles');
ylabel('Load/Stress Level');
title('Removed No-Reversal Cycles');

Answer 1

[Nirupama Nagarathinam]

Hi @Elijah McNeil,

You will require the "x" axis data as well to replicate the plot. The data that you have attcahed contains only the "y" axis data. I have assumed some "x" values for the data you have provide and the corresponding code and figure are as follows:

%reading the data that conatins only Load level
y=readmatrix('Aero.txt'); 

% creating x array of the same size of y
x=ones(size(y));

% for the values of y that are repeating consecutively, I am assigning the
% same x values
for i=2:length(x)
    if y(i)==y(i-1)
        x(i)=x(i-1);
    else
        x(i)=x(i-1)+1;
    end
end

%finding the peaks of Load level and their index value
[ylocs,locs]=findpeaks(y);
[ymins,mins]=findpeaks(-y);

%The index values (locs and mins) that we got have to be reassigned to the
%corrsponding x values
for j=1:length(locs)
    locs(j)=x(locs(j));
end
for k=1:length(mins)
    mins(k)=x(mins(k));
end

%ploting the curve and the peaks on the same figure
plot(x,y)
hold on
plot(locs,ylocs,'*r',mins,-ymins,'*r',"MarkerSize",3)

%figure title and labels
xlabel('Cycles');
ylabel('Load/Stress Level');
title('Removed No-Reversal Cycles');

The Cycles (x) values I have assumed might be different from the original, Otherwise the plot is very much similar to the one you are trying to replicate.