Adding a horizontal line to a plot

18 次查看（过去 30 天）
Simone
Simone 2014-12-6
评论： Star Strider 2014-12-6
How do you use the line function to add a horizontal line to a plot?
For example,
To add a horizontal line to easily point out the maximum value.
I am trying to use it in a nested for loop. This is my code so far:
y =[99;1;0];
beta = [0.005, 0.05, 0.1];
nu = [0.05, 0.075, 0.1];
options=odeset();
for i = 1:length(beta)
for index = 1:length(nu)
[T,Y] = ode45(@sir_ode,[0 30], y,options,beta(i),nu(index));
figure
plot(T,Y)
xlabel('Time(days)')
ylabel('Population(%)')
legend('susceptible','infected','recovered')
title_name =sprintf('Beta = %.3f Nu = %.3f', beta(i), nu(index));
title(title_name)
% finds max infected values
infected_values = Y(:,2);
max_infected(i,index) = max(infected_values);
% find max time
index_number(i,index)=find(infected_values ==max(infected_values));
max_T(i,index) = T(index_number(i,index));
line([max_T(i),max_T(i)], ...
[0,max_infected(i)],'Color', [0 1 0])
end
end
Thank you.

请先登录，再回答此问题。

采纳的回答

Star Strider
Star Strider 2014-12-6
I couldn’t run your code. You can do something like this to plot a horizontal line at the maximum:
x = linspace(0,pi);
y = sin(x);
ymax = max(y);
figure(1)
plot(x, y, '-b')
hold on
plot(xlim, [1 1]*ymax, '-r')
hold off
axis([xlim 0 1.1])

更多回答（1 个）

Image Analyst
Image Analyst 2014-12-6
Your line is a vertical line because both the x values are the same. To get a horizontal line, from the x=0 (y) axis to the peak, you could do
[maxY, indexAtMaxY] = max(infected_values);
x1 = 0;
x2 = T(indexAtMaxY);
line([x1, x2], [maxY, maxY], 'Color', 'g', 'LineWidth', 2);
  1 个评论
Image Analyst
Image Analyst 2014-12-6
Needless to say, all that code about "index_number" is unnecessary so get rid of it.

请先登录，再进行评论。

类别

在 Help Center 和 File Exchange 中查找有关 Annotations 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by