On ubuntu, plot() does not create figure

I just upgraded ubuntu to 20.04 and reinstalled matlab. The plot function does not create a figure window. If I create a figure window with command <figure>, a figure window does appear, but then plot() command does not a draw a plot in it.

[Ameer Hamza]

what if you also input the axes handle to the plot() object. Something like this

fig = figure();
ax = axes(fig);
plot(ax, rand(1,10));

[Geoffrey Rogers]

Thank you Ameer for your response. Unfortunately it still doesn't plot!

[Wouter Verstraelen]

See this one: it's an annoying (but known) issue

https://www.mathworks.com/matlabcentral/answers/216942-plotting-and-opengl-error-on-linux-how-to-resolve

Answer 1

[Gayathri]

Hi @Geoffrey Rogers,

I understand that you are facing issues in the "plot" function to generate a "figure" in MATLAB on Ubuntu OS.

Please refer to one of the below mentioned workarounds to resolve the issue.

1. Create a file named "java.opts" in the directory where MATLAB is executed (Eg: /usr/local/MATLAB/R2024b/bin/glnxa64) and include the following line.

-Djogl.disable.openglarbcontext=1 

2. Run MATLAB from the terminal using the following command to override the graphics driver.

export MESA_LOADER_DRIVER_OVERRIDE=i965; matlab 

3. Launch MATLAB with software OpenGL by using the following command.

matlab -softwareopengl 

4. Turn off anti-aliasing for figures by setting the "GraphicsSmoothing" property to "off" .

set(gcf, 'GraphicsSmoothing', 'off');   

You can also refer to the following MATLAB Answer to learn more about the workarounds.

https://www.mathworks.com/matlabcentral/answers/216942-plotting-and-opengl-error-on-linux-how-to-resolve

For more information, refer to the following MathWorks Documentation to learn about ‘Resolving Low-Level Graphics Issues’.

https://www.mathworks.com/help/matlab/creating_plots/resolving-low-level-graphics-issues.html

Hope you find this information helpful.

Answer 2

[Ali]

num = [1];

denum = [1 3 1];

g = tf(num, denum);

% Closed-loop system without controller

sys = feedback(g, 1);

figure;

step(sys);

drawnow;

hold on;

title('Step Responses');

xlabel('Time (seconds)');

ylabel('Amplitude');

grid on;

% PID Controller with manual gains

kp = 1;

ki = 1;

kd = 1;

p_manual = pid(kp, ki, kd);

% Closed-loop system with manual PID controller

sys_manual = feedback(p_manual * g, 1);

step(sys_manual);

% PID Tuning

p_tuned = pidtune(g, 'pid');

disp('Tuned PID Gains:');

disp(p_tuned);

% Closed-loop system with tuned PID controller

sys_tuned = feedback(p_tuned * g, 1);

step(sys_tuned);

% Add legend to distinguish responses

legend('Without Controller', 'Manual PID', 'Tuned PID');