MATLAB: Command Window (Whole Program Iterations)

command windowdebuggingiterations

Is it possible to check the whole history of a program which has let say i=20000 iteration. I have tried to debug the code but everything works fine till i=200 but i can't go till 20000.

The thing is when the program finishes, i can only see last couple of hundred iterations.

Is there anyway,i can check the whole program iteration(other than debugging)

Best Answer

There are at least two approaches that you can take in this situation:

(1) Use "cell mode". Use a conditional breakpoint to stop the code just before it hits the bad iteration. Then, enclose the failing part of the code in a cell (surrounding by "%%" before and after), and you can execute only the failing part. When it crashes, it will not take you completely out of the program.

(2) Save the workspace, and start from there each time. Again, use a conditional breakpoint to stop just before the bad iteration. Save the workspace. Then, instead of running the code for the first 200 iterations, just load the workspace, and run the rest of the code from there.

Related Solutions

MATLAB: Want to limit the lines of output. (for example, output after every 1000 iterations)

Hi Brian, your loop has a number of places where arrays are growing inside a loop. I believe this is the main reason why your code runs for 25 seconds. Things will run much faster if you preallocate. In fact, try the code below which should be almost instantaneous:

tstop=25; dt=0.001;
m=2; k=5; b=1;
pos=20; vel=3;
time = 0:dt:tstop;
out = zeros(length(time),4); % This is the big time-saver
out(:,1) = time';
for i = 1:length(time)
    acc= -(k/m)*pos -(b/m)*vel;
    out(i,2:4) = [acc vel pos];
    vel = vel + acc*dt;
    pos = pos + vel*dt;
end

Now, there are further speed-ups that could be made, but I've tried to keep the code similar to your original.

If you need the last row displayed to the screen once every 1000 iterations, then add this small if-statement inside the for-loop:

      if mod(i,1000)==0
          disp(out(i,:))
      end

I hope that answers the question

MATLAB: Stopped in debugger question

You could give the command

dbcont

and see what happened. Or you could give the command

dbstack

to see where it thought it was stopped.

Best Answer

Related Solutions

MATLAB: Want to limit the lines of output. (for example, output after every 1000 iterations)

MATLAB: Stopped in debugger question

Related Question