Making the Trend Equal??

Line two is upside down as compared to line one

And as shown above,

I want to make Line 2 the same as Line 1.

The picture above is my guess.

Do you have any mathematical methods or other methods?

My English is not good sorry.

Answer 1

[Image Analyst]

You can fit a line through curve 1. Then subtract the max of curve two and add the fitted line to it.

coefficients = polyfit(x1, y1, 1); % Fit a line.
% Get the line at locations where you have x2.
line1 = polyval(coefficients, x2);
% Find the max of curve 2.
y2max = max(y2);
% Make output curve (curve 3)
y3 = y2 - y2max + line1; % Tilt curve 2 upwards at the slant of curve 1

If you need more help, please attach the two curves in a .mat file with the paper clip icon.

[Kang Min Kim]

Thanks for the reply But I want to adopt this answer, but I get an error. What should I do?

[Kang Min Kim]

>> t = 0:300;
dailyFluct = gallery('normaldata',size(t),2); 
sdata = cumsum(dailyFluct) + 20 + t/100;
figure
plot(t,sdata);
legend('Original Data','Location','northwest');
xlabel('Time (days)');
ylabel('data');

I'd like to make this graph the same as the question I posted.

I don't know how to turn the graph upside down.

Please excuse me for that. Thank you.

[Image Analyst]

Your code makes this plot:

Tell me which is curve 1 (the top one), which is curve 2 (the middle one), and then I can tell you how to make curve 3 (the bottom one).

[Kang Min Kim]

Curve 2 is the upside down of that curve

I don't know how to do the upside down, sorry

This is curve 2

But this is just a change of axis

I'm not inverting the data(value)

I do not know how to do upside down data(value)

sorry

[Image Analyst]

Do you mean something like this:

clc;    % Clear the command window.
clear all; % Including global variables.
close all force;  % Close all figures (except those of imtool.)
workspace;  % Make sure the workspace panel is showing.
filebrowser;
format short g;
format compact;
fontSize = 14;

t = 0:300;
dailyFluct = gallery('normaldata',size(t),2); 
sdata = cumsum(dailyFluct) + 20 + t/100;

figure
subplot(1, 3, 1);
plot(t, sdata, 'b-', 'LineWidth', 2); % Plot original y data
% legend('Original Data','Location','northwest');
grid on;
xlabel('Time (days)');
ylabel('data');
title('Original data', 'FontSize', fontSize);

coefficients = polyfit(t, sdata, 1); % Fit a line.
% Get the line at locations where you have x2.
line1 = polyval(coefficients, t);
hold on;
plot(t, line1, 'r-', 'LineWidth', 2); % Plot line
legend('original y', 'Line through y');

% Find the max of curve 1.
y1min = sdata(1);

% Make the upside down data.
y2 = -sdata;
subplot(1, 3, 2);
plot(t, sdata, 'b-', 'LineWidth', 2); % Plot original y data
hold on;
plot(t, line1, 'r-', 'LineWidth', 2); % Plot line
plot(t, y2, 'c-', 'LineWidth', 2); % Plot upside down (negative) data
grid on;
title('Upside down data', 'FontSize', fontSize);

% Shift y2 upwards so that the first points start at the same y location.
y2 = y2 + 2 * y1min;
plot(t, y2, 'm-', 'LineWidth', 2); % Plot line
legend('original y', 'Line through y', 'Negative y', 'Negative y shifted upwards');

% Make output curve (curve 3)
y3 = 2 * line1 + y2 - 2 *y1min; % Tilt curve 2 upwards at the slant of curve 1
subplot(1, 3, 3);
plot(t, sdata, 'b-', 'LineWidth', 2); % Plot original y data
hold on;
plot(t, line1, 'r-', 'LineWidth', 2); % Plot line
plot(t, y3, 'm-', 'LineWidth', 2);
grid on;
title('Both original and Upside down data', 'FontSize', fontSize);
legend('original y', 'Line through y', 'y3, tilted upwards');

[Kang Min Kim]

thank you for your answer

I want to replace line through y with the moving average(30days) of original y.

I would appreciate it