Variable changes value after using load

I've been writing a script that runs a function with numerous subfunctions and I've been careful to not use global variables. At one point in the main function a few matrices saved as .mat are loaded if they do not exists in the workspace. The strange thing is that a variable of mine: maxnumsource = 2; That is one of the input parameters in that defines in the script that runs the main function changes value and is somehow redefined as maxnumsource = 1; after doing the load command. I wrote out the values of the variable right before and after the load and somehow it's redefined! Now the even stranger thing is that when I changed the name to maxnumsources with the added 's' this didn't happen anymore. So I 'fixed' the problem but I would like to know why this happens so I can avoid this in the future. And before anyone asks: No the loaded variables were not named maxnumsource.

Thanks

[Dishant Arora]

Attach your code.

[dpb]

...loaded variables were not named maxnumsource.

The crystal ball says it was by accident during debugging or testing by a save that inadvertently included the variable.

Execute

whos -file 'yourmatfile'

and see. You could check for how many and which ones were accidentally contaminated automagically by

d=dir('*.mat');
for i=1:length(d)
   s=whos('-file',d(i).name,'maxnum*')
   if ~isempty(s)
     for j=1:length(s)
       disp([d(i).name 'contains ' s(j).name]
     end
   end
 end

I'm betting you'll find at least one case...

[Elías Heimisson]

My bad, this was actually a very silly mistake. When I saved the matrix which I then load I forgot to include the variable name. So all variables that were in the workspace when I calculated this matrix were saved including maxnumsource. This matrix was calculated in a seperate script so I was looking for the bug in the wrong place.

[dpb]

Told ya'... :)

Easy mistake to make; no problem...

Answer 1

[Image Analyst]

Always accept the results of load() into a structure so that you don't poof variables into existence and cause problems like you did.

storedStructure = load(fullFileName);
var1 = storedStructure.var1;
var2 = storedStructure.var2;

For example if there was a var3 in there, it's not going to blast over any var3 that I already have because I didn't explicitly allow it.

[dpb]

Most excellent point, IA! +1