Is it possible to have a command in common lisp which somehow temporarily pauses the execution. In matlab you can achieve this by using the pause command, in which you can also set the time to pause as well. What I want to do is that, in a loop I will print my result to the top-level then wait for x-seconds (I am going to set the x), do the next iteration, print and wait and so on.
Thank you very much in advance.
See SLEEP.
You can either use SLIME, interrupt the execution of the program and
eval an expression in frame to modify the value of some variables « by hands »
or use the exceptions system and provide a restart which will ask to the
user the new values.
Related
What is the difference between "step out (shift+F11)" and "continue (F)" in MATLAB debugger? When I debug a MATLAB function, both are triggering the cursor to come out of the loop. What is the exact difference between these two?
Continue (dbcont) will cause the program to resume execution and will only stop once it encounters another breakpoint.
Step-Out (dbstep out) will cause the currently executing function to continue and will automatically pause in the calling function regardless of whether you have a breakpoint there or not. Notice that this is referring to stepping out of a function and not a loop.
In your case, I'm assuming you only have a single function (or script) and therefore if you have no manual breakpoints after calling dbcont or dbstep out, they are going to have the same result since they will both just run the rest of the script to completion.
Is there any way to stop the execution of a matlab program from the debugger like ctrl+c does, but then being able to continue execution (like you can in say c#)?
If not, is there any better way to workaround this other than trying to pre-emptively set break points or dbstop statements in your matlab code?
I would like to be able to interrupt a long running simulation to look at the current state and then continue the simulation.
The two options I'm currently using/considering are
dbstop commands (or (conditional) breakpoints) in the code.
Drawback is that sometimes I don't want to stop the simulation for a few hours, sometimes want to stop after only a few seconds (and I don't necessarily know that in advance) and this doesn't work well with this approach: If I set the break condition to break every 5 minutes, I can't leave matlab running for hours without interaction. If I set the condition to higher, I have to wait too long for the condition to hit.
include code to save the workspace every few seconds/minutes and import the workspace into a second matlab instance. Drawback is that this is a huge hassle and also doesn't necessarily allows me to resume the simulation with the state of the saved workspace then step through the code for a few iterations.
I'm hoping there is a better solution than either of the 2. Thanks for any advice!
Edit: I think what I'm going to do is write simple matlab function that checks an environment variable or a file on disk every iteration and calls dbstop if I set a flag in this file or env. This way I can control when (and if needed which of several) the breakpoint hits from outside matlab by editing the file. Messy, but should work.
This is not necessarily the best way, but you could simulate a file-based signal/interrupt framework. It could be done by checking every once in a while inside the long simulation loop for the existence of a specific file. If it does, you enter interactive mode using the keyboard command.
Something along the lines:
CHECK_EVERY = 10; %# like a polling rate
tic
i = 1; %# loop counter
while true %# long running loop
if rem(i,CHECK_EVERY) == 0 && exist('debug.txt','file')
fprintf('%f seconds since last time.\n', toc)
keyboard
tic
end
%# ... long calculations ...
i = i + 1;
end
You would run your simulation as usual. When you would like to step in the code, simply create a file debug.txt (manually that is), and the execution will halt and you get the prompt:
2.803095 seconds since last time.
K>>
You could then inspect your variables as usual... To continue, simply run return (dont forget to temporarily rename or remove the file). In order to exit, use dbquit
EDIT: Just occurred to me, instead of checking for files, an easier solution would be to use a dummy figure as the flag (as long as the figure is open, keep running).
hFig = figure; drawnow
while true
if ~ishandle(hFig)
keyboard
hFig = figure; drawnow
end
%# ...
pause(0.5)
end
With the release of R2016a, you can just hit the Pause button in the code editor and it will halt right away. The keyboard shortcut is Ctrl+F5.
To pause the execution of a program while it is running, in the Editor tab, click the Pause button. MATLAB pauses execution at the next executable line*.
When your code is running, the Start button will turn into a pause:
Another change with this release is the ability to add/remove breakpoints while running. Previously you couldn't do this, apparently.
You can set a conditional breakpoint in the MATLAB Editor. You can also use DBSTOP to do this. For example, this will set a conditional breakpoint in the file myFcn at line 20 which will stop execution when a loop variable i is a multiple of 500:
dbstop in myFcn.m at 20 if rem(i,500) == 0
Then you can continue execution after you inspect some of your variables.
If saving the workspace to a file is a good proxy for what you want, how about making a simple GUI with a toggle button. In your code, check the state of the button. If the button is depressed, save the state, update a static text to reflect time stamp of last save, unpress the button. Optionally, have a conditional breakpoint based on the state of that toggle button.
Here is an alternate solution using the waitinput File Exchange submission.
The advantage is that you can use it from whithin the current session or in cases where it is troublesome to set up a file. Also it won't leave a file behind on the computer.
The downside is there as well unfortunately, you need to wait for the checking moment before you can terminate and it costs a little bit of time.
for t = 1:10
pause(3) %Doing some calculations
str = waitinput('Enter 1 if you want to stop ',5);
if ~isnan(str)
keyboard; % Enter dbcont if you want to continue from here
end
['moving on, it is now: ' datestr(now)]
pause(3) %Doing some more calculations
end
If you want, you can prevent lines being printed to the screen. In this case you need to enter the input at the time the figure window is open (Look in your start bar on windows).
To summarize, the short code that you can put somewhere like a conditional breakpoint would be:
if ~isnan(waitinput('',5))
keyboard;
end
After certain version (I don't know which one exactly):
Windows: Ctrl + F5
Mac: Command + F5 (I guess)
Unix: I am looking for answer too
After 2016a, there is a button for that on the interface too.
This question already has answers here:
Stop and continue execution from debugger possible?
(6 answers)
Closed 8 years ago.
Strg+C stops and kills a Matlab script (at least sometimes). But is there a way to stop a Matlab, take a look at some variables and continue the calculation?
I am not talking about just setting a breakpoint. I want my script, let’s say run for couple hours come back to it hit some buttons that stops the calculations take a look at some variable and then continue the calculation.
I tried to find out if there is some shortcut key for this – I am quite sure there isn’t.
Now I was thinking about including an if-case that looks if a certain button was pressed by the user. If so there would be a useless k=0 line and a breakpoint on it. And if no one is pressing this button the loop would continue. But this is where my limited Matlab knowledge leaves me. I don’t know if there is a way to ask for a user-button press but don’t wait for a button press like in the function input. Also I just have a running script, I don’t have any GUI.
To drop to the command prompt you need the command keyboard and then type return when you have finished (you don't need a breakpoint). The tricky bit is how to trigger it. There a few options. The easiest is to open a figure window. The following code halts the process when any key is pressed.
keyDownListener=#(src,event) keyboard;
fig = figure;
drawnow
set(fig,'KeyPressFcn',keyDownListener)
for p=1:10000
%do some thing
end
You can modify this to test for a specific key since the keypress is contained within the event struct.
To use no figure gui at all its more of a problem. I'm not aware of a non blocking keyboard input method. A mex file the runs kbhit() in C might do it, but kbhit() is not standard C so it would only work on Windows. An easier option maybe to test for the presence of a file.
for p=1:100000
if exist(fullfile(pwd,'halt.tmp'),'file')
keyboard
end
%do something here
end
This drops to the debug console when halt.tmp is created in the current directory.
Other potential methods could involve using multiple threads to read 'input' (either the Parallel computer toolbox or undocumented Java code), or using http://psychtoolbox.org/ as mentioned by #bdecaf
This question already has answers here:
Stop and continue execution from debugger possible?
(6 answers)
Closed 6 years ago.
In MATLAB, I'm running some code which takes a while to run. I'd like to pause the code to check on some variable values. Is there a way I can do this without having to re-run the code from the beginning? I don't want to terminate the program; just pause it.
You can halt execution and give a command prompt in two ways of which I am aware:
Putting keyboard in your code where you want to stop.
Setting a breakpoint.
You can resume and stop execution with dbcont and dbquit, respectively. To step forward, use dbstep. dbstack lets you see where you are. There are many more commands. The help page for any of these will give you other suggestions.
As Dennis Jaheruddin has pointed out, dbstop also has several useful features worth trying. In particular is the ability to set conditional and global (any line meeting a criterion) breakpoints via the dbstop if syntax. For example, dbstop if error will break to a debugging command prompt on any error. One suggestion he made, which I now do, is to put dbstop if error into startup.m so that this behavior will be default when you start MATLAB. You may need to create this file in a userpath folder; edit(fullfile(regexp(userpath,'^[^;]*','match','once'),'startup.m')).
One way to achieve what you're looking for would be to use code sections (also known as code cells), where you divide your code into sections divided by lines with two percent signs (%%).
Then, in the editor, you can press ctrl+enter to execute the current code section, and ctrl+up/down to navigate between sections.
Well there is the pause command, but then you cannot check for the variable contents in the workspace because the program is running.
What you probably want is to set a breakpoint (See the Debug menu / key F12).
At a breakpoint matlab pauses the program and enters debugging mode in which you can see and edit the variables. Once finished, you can resume the program where it was paused.
I'm not sure about Windows users but if you're running Linux you can start Matlab in a terminal using
matlab -nodesktop
then once Matlab has started, cd to your project directory and start your Matlab script. Now whenever you want to pause execution you can use ctrl-Z. Then to resume type fg. I hope this helps.
My question is, how do I stop a script by a pressing a GUI button? I already tried to write a code that simulates "CTRL+C" press, but it doesn't work.
I'm not sure there's a way to stop another script from being called. One alternative would be to set a global variable that's periodically checked by the script you wish to stop. If you set the value of a "stop processing" variable to true in your callback, the other script could stop if it found that it was supposed to stop.
Edit
If you'd like to have a GUI option to stop an ongoing process, I would recommend you take a look at something like STOPLOOP on the MATLAB File Exchange.
I won't write the code for you but here's a high-level way to accomplish this:
Display a waitbar with a button on it. Create a callback function for the button which sets a flag to true.
Begin computation inside of a for-loop. In the loop:
1. update the waitbar.
2. call the drawnow function so that the callback is executed properly. Remember MATLAB is single-threaded, so this is necessary or the callback will not execute until the script finishes.
3. perform any other computation
4. check for the flag set to true. if it is true, return to stop execution.
The flag could be a global variable, or a handle-based object (so that it is passed by reference).
EDIT:
This answer is not applicable for the current question.
This answer is applicable only for scripts having the first line = #!/usr/bin/matlab
use pkill without option will send a TERM signal:
pkill yourscriptname
If you really want the same signal as CTRL+C then:
pkill -3 yourscriptname
If your script still does not stop, you can use the most aggressive signal KILL:
pkill -9 yourscriptname
Of course, if you known the PID (Process IDentifier), you can simply use kill:
kill yourPID
kill -3 yourPID
kill -9 yourPID
You can have more info about signals using one of these commands:
man 7 signal
kill -l
info signal
I don't do a lot of GUIs, but for debugging purposes I would try to set the button callback to #keyboard. That is, something like:
set(handleToGuiButton,'Callback',#keyboard)
To actually stop execution you would need to somehow communicate this button press into the loop that was executing, for example via global variables, or something fancier (e.g. https://stackoverflow.com/a/8537460/931379)
But I would honestly look at the stoploop link (from another answer) before going down any of these routes.