Plot produces blank figure.

Taking a course and running through a very simple example, but my Figure opens with just a blank black image. The data looks like it is loaded properly into X and y. Any guidance would be great.

clear ; close all; clc

fprintf('Plotting Data ...\n')

data = load('ex1data1.txt');

X = data(:, 1);  y = data(:, 2);  m = length(y);

% Plot Data

plotData(X, y);

fprintf('Program paused. Press enter to continue.\n');

pause;  

% Function %

function plotData(x, y)

figure; 

plot(x, y, 'rx', 'MarkerSize', 10);

ylabel('Profit in $10,000s');

xlabel('Population of City in 10,000s');

end

[Adam]

Have you stepped through with the debugger to look at x and y?

It's difficult to suggest anything as we don't have your data and nothing jumps out from the code to me as being blatantly wrong.

Also have you tried it without the 'pause' instruction? It may just be a case of the plot not being drawn yet because it is paused.

[Walter Roberson]

pause() triggers drawing so that is not the reason.

Answer 1

[David Rainbeau]

I tracked this down to being a video card issue. Was led to this conclusion through http://www.mathworks.com/help/matlab/ref/opengl.html. When I changed from opengl hardware to opengl software, the plot worked properly.

Even though my Matrox M-9148 card only supports OpenGL 2.0 (not 2.1), once I update the drivers, the hardware works without having to rely on using software.

[Nicholas Jackson]

Thanks! This fixed mine too