Plotting very slow and took long time to launch plot tool

I am plotting 50 graphs in the same plot with these few lines. The data are already in the workspace.

figure; hold on

for n = 1:50

plot(x, y,'LineWidth',2.0);

hold on

end

The figure window shows up within 5 seconds, but it takes MATLAB 3 minutes to populate the graph window with the graphs. Additionally, when I try to use the plot tools to modify the figure, each icon I click or each action I did takes ~ 10 seconds to act, including some simple action like moving the legend position or click to select a specific graph. My computer practically froze while waiting.

I have a pretty fast computer - an i7 8th generation with 16 GB RAM. I am running on MATLAB R2017b. Running other high memory usage program doesn't have this issue. I have never had this problem with R2017b on another supposedly slower computer - i3 with 32 GB RAM.

I am more of trying to trouble-shoot if this is the problem of the computer or with MATLAB. If anyone had similar problem with R2017b hopefully the answer I got would be helpful. Thanks MATLAB community!

[KSSV]

What are the dimensions of x,y ?

[Greg]

Graphics display takes a back seat to CPU activity, and will not flush until the CPU has idle time. There are a wealth of articles that will explain this better than I am going to here. But, start with a look at the documentation for drawnow.

---Sorry, thought I saw you trying to use 50 separate figures. Above comments mostly not applicable. I'm with KSSV - if x and y are extremely large, you're going to have performance issues.

[Greg]

Also, you've already called hold on before the loop, doing it again inside is silly.

[Melissa Chen]

Thanks Greg. my x is a [1x1801] and my y is a [50 x 1801]. I did thought 50 maybe too much so I went back and try to plot 10 instead. The amount of time it takes to show up is similar to plot with 50 which is something I never seen before with my old computer. But you made a good point of the CPU activity and maybe there's something that's feeding off CPU when I am plotting with matlab.

Answer 1

[Greg]

Given information from your comments that y is 50x1801, the command

plot(x,y,'LineWidth',2);

Will already plot all 50 rows of y against x. Doing it inside a loop gives you 50*50 = 2500 lines in your figure.

Replace all of your code with the one line above.