% Demonstration NMR spectrum smoothing with Whittaker smoother
% Optimal smoothing by cross-validation
%
% Paul Eilers, 2003

% Get the data
data = load('nmr_with_weights_and_x.csv');
x = data(: ,1);
y = data(:,2);
evenly_space_weights = data(:,3);
random_weights = data(:, 4);



[z_even, ~] = whitsmddw(x, y, evenly_space_weights, 2e4, 2);

writematrix(z_even,'output_x_y_and_weights_2e4_2.csv')

[z_random, ~] = whitsmddw(x, y, random_weights, 2e4, 2);

writematrix(z_random,'output_x_y_and_random_weights_2e4_2.csv')


% Plot data and smooth
subplot(1, 1, 1);
plot([z_even-10 y] )    % Downward shift for visibility
hold on;
plot([z_random-10 y] )
title('NMR spectrum and optimal smooth')
xlabel('Channel')
ylabel('Signal strength')