Why is my deployed MATLAB application unable to generate a new figure? - matlab

I have built a GUI with some text boxes and a pushbutton. When I execute the GUI from MATLAB, it produces the desired plot on a separate window. The plot is created by a function that is stored in the same directory and is called in the callback function of pushbutton.
When I package it with the .m file of the GUI as the main file, I get an exe. When this exe runs, it normally takes data from data source (sqlserver) but then does not give the plot in a separate window as within matlab (also not in the same GUI window). There is a sound and from the behaviour it seems that the plots appears and vanishes in a very short time. But this is my perception and may be wrong, maybe it is some error message that is suppressed.
What can I do to solve this?

You've run into the problem discussed here in this post
Once the code is finished evaluating it cleans up, including closing the window you created. One solution would be to pause your script right after plotting.
Here's a discussion of many functions that can be used to pause execution with a GUI.

Related

X11 MATLAB Display Figure

I know it's possible to forward any output from a remote machine to a local one by using the X11 forwarding remote tunnelling, so that when you run a MATLAB command it will display all the graphical outputs back to the machine you've connected from.
My question is:
Is there any MATLAB command to just output the figures (e.g., plot,surf,etc.) without displaying any other graphical object (i.e., the main interface)?
In practice, I would like to interact with MATLAB by using the command line (as shown below) and forward back only the figures.
MATLAB cannot display figures without its own figure-GUI, so the answer to your question would be no.
However: there is a workaround: create an invisible figure using f=figure('visible', 'off'), then plot your data, and finally use saveas(f,filename,fileextention). Don't forget to close(f) your figure after saving, to free the RAM. You'll now have a figure in your file directory, which you can display using your favourite visualising tool, which might even be possible through a call to system, although I have never tested that.

Matlab Simulink generating no output

I am learning Matlab Simulink. Here is the basic simulation that I'm doing.
When I pressed Start Simulation I get these errors.
Then as suggested here I changed my settings to this.
But now when I am simulating, a warning sound beeps but no error message is showing in Matlab Command Window and I am not getting my output.
Where is the problem and how can I solve it??
I am using Matlab 7.10.0(R2010a).
You're not getting any output in the Command Prompt because you haven't specified any sinks to export the data to the Workspace and so workspace variables aren't created. You're only able to see the output in the Scope tool in Simulink but this data hasn't been exported to your workspace. In Simulink, there is a To Workspace block that you can use to pipe the sinusoidal data to the workspace. In the Sinks section of the Library Browser, choose the To Workspace block and connect the output of the Sine Wave black to this block... so:
To make things compatible, make sure you choose the option to output your data as an array format instead of time series... well I find that the array option is better. Open up the To Workspace block and change the output to Array:
When you do this and run the simulation, you should see a variable called simout in your workspace that captures this data and tout that measures the time steps of each output amplitude in your sine data:
You can then plot the data by doing just plot(tout, simout);
Minor Note
The "warning" beep happens because MATLAB is telling you that Simulink has finished the simulation. Nothing wrong is happening.

MATLAB command line output not following

There is something very simple that can be very upsetting occasionally.
I sometimes want to keep track of the outputs of an algorithm at each iteration, so within a for loop, I use disp command of MATLAB to output some information. However, although there is quite a bit of time between the calling of dispcommands, the MATLAB command window falls behind and I need to use the mouse to keep up with it manually. Do you know if there is any way to have it not fall behind?
Thanks,
It really shouldn't fall behind, but I could see this happening if the computations are intensive and the MATLAB JVM, which drives the GUI, does get the resources to update the command window.
The following command may be of help:
drawnow update % or just drawnow
According to the documenatation page, this "causes only user-interface objects to refresh, if needed". If that fails, try just drawnow with no arguments to see if it helps to flush the entire system event queue, including graphics updates.
If that doesn't work you could insert a pause(0.01) or something similar as a last resort.
It shouldn't fall behind if you don't use the mouse at all. However, I often use the waitbar for this purpose.
FEX also has several text & GUI progress bars.

How to break matlab script execution? [duplicate]

This question already has an answer here:
How to abort a running program in MATLAB?
(1 answer)
Closed 7 years ago.
I write a long running script in Matlab, e.g.
tic;
d = rand(5000);
[a,b,c] = svd(d);
toc;
It seems running forever. Becasue I press F5 in the editor window. So I cannot press C-Break to stop in the Matlab console.
I just want to know how to stop the script. I am current use Task Manager to kill Matlab, which is really silly.
Thanks.
Matlab help says this-
For M-files that run a long time, or that call built-ins or MEX-files that run a long time, Ctrl+C does not always effectively stop execution. Typically, this happens on Microsoft Windows platforms rather than UNIX[1] platforms. If you experience this problem, you can help MATLAB break execution by including a drawnow, pause, or getframe function in your M-file, for example, within a large loop. Note that Ctrl+C might be less responsive if you started MATLAB with the -nodesktop option.
So I don't think any option exist. This happens with many matlab functions that are complex. Either we have to wait or don't use them!.
If ctrl+c doesn't respond right away because your script is too long/complex, hold it.
The break command doesn't run when matlab is executing some of its deeper scripts, and either it won't log a ctrl sequence in the buffer, or it clears the buffer just before or just after it completes those pieces of code. In either case, when matlab returns to execute more of your script, it will recognize that you are holding ctrl+c and terminate.
For longer running programs, I usually try to find a good place to provide a status update and I always accompany that with some measure of time using tic and toc. Depending on what I am doing, I might use run time, segment time, some kind of average, etc...
For really long running programs, I found this to be exceptionally useful
http://www.mathworks.com/matlabcentral/fileexchange/16649-send-text-message-to-cell-phone/content/send_text_message.m
but it looks like they have some newer functions for this too.
MATLAB doesn't respond to Ctrl-C while executing a mex implemented function such as svd. Also when MATLAB is allocating big chunk of memory it doesn't respond. A good practice is to always run your functions for small amount of data, and when all test passes run it for actual scale. When time is an issue, you would want to analyze how much time each segment of code runs as well as their rough time complexity.
Consider having multiple matlab sessions. Keep the main session window (the pretty one with all the colours, file manager, command history, workspace, editor etc.) for running stuff that you know will terminate.
Stuff that you are experimenting with, say you are messing with ode suite and you get lots of warnings: matrix singular, because you altered some parameter and didn't predict what would happen, run in a separate session:
dos('matlab -automation -r &')
You can kill that without having to restart the whole of Matlab.
One solution I adopted--for use with java code, but the concept is the same with mexFunctions, just messier--is to return a FutureValue and then loop while FutureValue.finished() or whatever returns true. The actual code executes in another thread/process. Wrapping a try,catch around that and a FutureValue.cancel() in the catch block works for me.
In the case of mex functions, you will need to return somesort of pointer (as an int) that points to a struct/object that has all the data you need (native thread handler, bool for complete etc). In the case of a built in mexFunction, your mexFunction will most likely need to call that mexFunction in the separate thread. Mex functions are just DLLs/shared objects after all.
PseudoCode
FV = mexLongProcessInAnotherThread();
try
while ~mexIsDone(FV);
java.lang.Thread.sleep(100); %pause has a memory leak
drawnow; %allow stdout/err from mex to display in command window
end
catch
mexCancel(FV);
end
Since you mentioned Task Manager, I'll guess you're using Windows. Assuming you're running your script within the editor, if you aren't opposed to quitting the editor at the same time as quitting the running program, the keyboard shortcut to end a process is:
Alt + F4
(By which I mean press the 'Alt' and 'F4' keys on your keyboard simultaneously.)
Alternatively, as mentioned in other answers,
Ctrl + C
should also work, but will not quit the editor.
if you are running your matlab on linux, you can terminate the matlab by command in linux consule.
first you should find the PID number of matlab by this code:
top
then you can use this code to kill matlab:
kill
example:
kill 58056
To add on:
you can insert a time check within a loop with intensive or possible deadlock, ie.
:
section_toc_conditionalBreakOff;
:
where within this section
if (toc > timeRequiredToBreakOff) % time conditional break off
return;
% other options may be:
% 1. display intermediate values with pause;
% 2. exit; % in some cases, extreme : kill/ quit matlab
end

Disable plots in Matlab

I have some programs written in Matlab that I need to run several times for some reasons (debugging, testing with different input, etc...)
But, there are a lot's of graphs that are plotted by the programs and its various functions such that everytime I run the program, I have to wait for all the graphs to be displayed, which is very annoying and time consuming (especially when you are working with a small laptop).
After the program is executed, I close them with a close all.
So my question is:
Is there a way to disable all plots/figures/graphs in Matlab? either in the options, or by executing a certain code like disable plot and enable plot to ensure that no figures are being displayed.
I know that I can just browse the code and comment the plotting part, but I don't want to forget to uncomment.
Try some combination of the two commands:
set(gcf,'Visible','off') % turns current figure "off"
set(0,'DefaultFigureVisible','off'); % all subsequent figures "off"
The second one, if you put it near the beginning of your program, might do the trick for you. Of course, it is still creating the plots, which might be undesirable for computation time and/or RAM issues.
This is a classic reason to avoid Matlab when one can. It fosters bad programming design. To solve this problem correctly, you should create something that lets you "flip a switch" at the highest level of your program and control whether plots show or do not show. Perhaps it even has gradations of the show/don't show option so you can select different types of plots that do/do not show depending on what diagnostics you are running.
Ideally, you'd want this "flip a switch" creation to be a class that has access to visibility and plot functions of other objects. But because interactive object-orientation is so cumbersome in Matlab, it's often not worth the effort to develop such a solution, and most people don't think about this design aspect from the outset of their project.
Matlab would encourage someone to solve this by making flag variables like "isPlotVisible" or something, and creating functions that always accept such flags. I agree this is a bad design.
You could run matlab from the command line with:
matlab -nojvm
but then you don't get the GUI at all. Alternatively, you could write a file 'plot.m':
function h = plot(varargin)
h = [];
end
which doesn't do anything. If this is in the working directory (or somewhere else near the top of the path), then plot will call your function instead of the 'real' plot. You'd need to do the same from any other graphing functions you call.
The closest way I know of 'turning off plotting' would be a folder of such functions that you can add to the path to disable plotting, and remove to enable.
The previous methods are fine, but an easy and good habit to take is to use a "on/off parameter". So basically, at the beginning of your code, you can add something like:
DisplayFigure = 1; %1 = display, 0 = no display
After that, add "if DisplayFigure == 1 ... end" for all your plotting related commands, where the commands should be inside the if statement (the ... above). Hence you won't even compute the plots, which will save you a lot of time and memory. You just have to change the value of the variable "DisplayFigure" to plot or not the figures.