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How can adding a breakpoint cause an error?
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I'm having problems debugging Matlab code since when I add a breakpoint, I get an error that doesn't happen without the breakpoint:
In my code I have an if statement to detect questionable results and display a message to the command line, but otherwise let the code run which it does with no issues. There were a few questionable results (after many iterations of expected results) that I wanted to investigate so I put a breakpoint within that if statement; however, once I did that, there is a repeatable error regarding the assignment on the line previous to the if statement (so it never gets to the actual breakpoint). The code runs fine without a breakpoint, but has an error with the breakpoint - what causes this?? And how can I avoid it??
I also tried adding a questionableResults = 1 flag and using that to move the breakpoint to later (as below) and putting a breakpoint in the 'other code' and also after the 'if C' statement, but eventually I always get the same error as with the original breakpoint. As soon as I remove the breakpoint, it runs to completion with no errors.
for i = 1:largeNumber
(code to find value1 and value2)
if C
A = value1;
B = value2; % the error is for this line if there is a breakpoint
if A~= B;
disp(['Warning: ' num2str(A) ' is not the same as ' num2str(B)]);
*original breakpoint*
questionableResults = 1;
end
(other code)
if questionableResults
*test breakpoint*
end
end %if C
*test breakpoint*
end %for i
The error is: 'Assignment has more non-singleton rhs dimensions than non-singleton subscripts' and occurs on the with the assignment of B.
Any insight would be appreciated. Thanks!
1 Comment
Matt J
on 26 Jan 2013
It doesn't seem like you've shown your actual code. There are no subscripts in the line where you claim to see the error. A few preliminary recommendations
Answers (3)
Jan
on 25 Jan 2013
Edited: Jan
on 25 Jan 2013
The paraphrased pseudo code is less suitable for debugging in a forum. It is very likely that the problem is exactly in this parts of the code you have hidden.
Do you have any eval() or assignin() in your code? The dynamic creation of variables works differently in debug and non-debug mode.
4 Comments
Matt J
on 28 Jan 2013
Trap this error with DBSTOP IF ERROR. Then evaluate
>> f, 1:length(objc2D)
Matt J
on 26 Jan 2013
Edited: Matt J
on 26 Jan 2013
Is it possible that you've run, reached a breakpoint, then run again without first quitting out of DEBUG mode?
3 Comments
Matt J
on 26 Jan 2013
No persistent variables either? What if you do "clear functions" first, and then set the breakpoints again and run?
Image Analyst
on 26 Jan 2013
Edited: Image Analyst
on 26 Jan 2013
Set a breakpoint at this line:
B = value2; % the error is for this line if there is a breakpoint
before you execute it, say this in the command line:
K>> whos value2
K>> size(value2)
Tell us what it says.
2 Comments
Image Analyst
on 29 Jan 2013
Now do the same thing for out2d.objc2 (instead of objc2). You're saying that it's a 2D array, but is it really?
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