Hey @Luis Martin Romero, Assuming you have your original data (let's call it x_data and y_data) and a list of specific X-values that are your "breaking points," here's how you can find the corresponding Y-values and plot them in MATLAB
% 1. Assume you have your original data:
x_data = 1:0.5:10;
y_data = sin(x_data) + x_data./5 + randn(size(x_data))*0.2; % Some example noisy data
% 2. And you have identified specific "breaking points" (x-values):
breaking_points_x = [2.5, 4.0, 7.5, 9.0];
% --- Get the corresponding Y-values ---
% Method 1: Using 'ismember' (Good for exact matches or when order doesn't matter)
% This is generally the most straightforward for finding Y-values for specific X-values.
[~, idx] = ismember(breaking_points_x, x_data); % Find indices of breaking_points_x in x_data
% ismember returns two outputs:
% 1. A logical array indicating which elements of breaking_points_x are in x_data.
% 2. The index in x_data for each element of breaking_points_x.
% We only need the second output, so we use ~ for the first.
breaking_points_y_ismember = y_data(idx); % Use these indices to get corresponding Y-values
disp('Y-values using ismember:');
disp(breaking_points_y_ismember);
% Method 2: Using 'interp1' (Essential if your breaking_points_x might not be exact matches in x_data)
% If your breaking_points_x values don't perfectly align with x_data, or you want to
% find Y-values for X-values that fall *between* your original data points,
% you'll need interpolation.
breaking_points_y_interp = interp1(x_data, y_data, breaking_points_x);
disp('Y-values using interp1 (interpolation):');
disp(breaking_points_y_interp);
% Note: If a breaking_points_x value is outside the range of x_data, interp1 will return NaN.
% You can specify an 'extrapolation' method for interp1 if you need values outside the range.
% --- Plot these points ---
% Create the initial plot of your original data
figure;
plot(x_data, y_data, 'b-', 'DisplayName', 'Original Data'); % 'b-' for blue line
hold on; % Keep the current plot active to add more elements
% Plot the identified breaking points on top of the original plot
% Using scatter is often good for emphasizing individual points
scatter(breaking_points_x, breaking_points_y_ismember, 100, 'r*', 'filled', 'DisplayName', 'Breaking Points (exact)');
% 'r*' means red asterisks, '100' is marker size, 'filled' fills the marker.
% If you used interpolation and want to plot those:
% scatter(breaking_points_x, breaking_points_y_interp, 100, 'go', 'filled', 'DisplayName', 'Breaking Points (interpolated)');
% Add labels and title for clarity
xlabel('X-axis');
ylabel('Y-axis');
title('Plot with Highlighted Breaking Points');
legend('show'); % Show the legend to identify the different plot elements
grid on;
hold off; % Release the plot to prevent further additions
% --- If you want to plot ONLY the breaking points ---
figure;
plot(breaking_points_x, breaking_points_y_ismember, 'r-o', 'LineWidth', 2, 'MarkerSize', 8, 'DisplayName', 'Breaking Points Only');
xlabel('X-axis');
ylabel('Y-axis');
title('Plot of Breaking Points Only');
legend('show');
grid on;
