feat(analysis): add comare frequencies function

.gitignore

@@ -4,6 +4,7 @@
 *.eps
 
 # Folders to ignore
+figures/
 data/wtFiles/*/*
 data/arduinoFiles/*
 data/ORIGINAL_RAW_DATA

utils/comparefrequencies.m

+function [allRelDiff, meanDiff, stdDiff] = comparefrequencies(ResData)
+    % COMAPREFREQUENCIES Compare the frequencies of the two sets (should be identical)
+    %   Todo
+
+    % ----------------------------------------------------------------------------------------------
+    % (c) Copyright 2022 University of Liege
+    % Author: Thomas Lambert <t.lambert@uliege.be>
+    % ULiege - Aeroelasticity and Experimental Aerodynamics
+    % MIT License
+    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+    allRelDiff = zeros(size(ResData));
+
+    for i = 1:size(ResData, 1)
+        for j = 1:size(ResData, 2)
+
+            allFreqF(i, j) = ResData(i, j).Front.trueFreq;
+            allFreqA(i, j) = ResData(i, j).Aft.trueFreq;
+
+            allRelDiff(i, j) = abs(ResData(i, j).Front.trueFreq - ResData(i, j).Aft.trueFreq) / ...
+                ResData(i, j).Front.trueFreq;
+
+        end
+    end
+
+    allRelDiff = abs(allFreqF - allFreqA) ./ allFreqF;
+
+    meanDiff = mean(mean(allRelDiff));
+    stdDiff = mean(std(allRelDiff));
+
+    figure('Name', 'Frequency differences');
+    hold on;
+    plot(allFreqF, allFreqA, 'ok', 'MarkerFaceColor', 'k');
+    xlim([1.5, 3.5]);
+    ylim(xlim);
+    plot(xlim, xlim, '--');
+
+    hold off;
+    grid on;
+
+    xlabel('f_{aft}  [Hz]');
+    ylabel('f_{front}  [Hz]');
+
+end